diff --git a/blockdag/blockheap.go b/blockdag/blockheap.go
index 4917d6390..f66919329 100644
--- a/blockdag/blockheap.go
+++ b/blockdag/blockheap.go
@@ -24,12 +24,26 @@ func (h *baseHeap) Pop() interface{} {
 	return popped
 }
 
-func (h baseHeap) Less(i, j int) bool {
-	if h[i].height == h[j].height {
-		return daghash.HashToBig(&h[i].hash).Cmp(daghash.HashToBig(&h[j].hash)) > 0
+// upHeap extends baseHeap to include Less operation that traverses from bottom to top
+type upHeap struct{ baseHeap }
+
+func (h upHeap) Less(i, j int) bool {
+	if h.baseHeap[i].height == h.baseHeap[j].height {
+		return daghash.HashToBig(&h.baseHeap[i].hash).Cmp(daghash.HashToBig(&h.baseHeap[j].hash)) < 0
 	}
 
-	return h[i].height > h[j].height
+	return h.baseHeap[i].height < h.baseHeap[j].height
+}
+
+// downHeap extends baseHeap to include Less operation that traverses from top to bottom
+type downHeap struct{ baseHeap }
+
+func (h downHeap) Less(i, j int) bool {
+	if h.baseHeap[i].height == h.baseHeap[j].height {
+		return daghash.HashToBig(&h.baseHeap[i].hash).Cmp(daghash.HashToBig(&h.baseHeap[j].hash)) > 0
+	}
+
+	return h.baseHeap[i].height > h.baseHeap[j].height
 }
 
 // BlockHeap represents a mutable heap of Blocks, sorted by their height
@@ -37,9 +51,16 @@ type BlockHeap struct {
 	impl heap.Interface
 }
 
-// NewHeap initializes and returns a new BlockHeap
-func NewHeap() BlockHeap {
-	h := BlockHeap{impl: &baseHeap{}}
+// NewDownHeap initializes and returns a new BlockHeap
+func NewDownHeap() BlockHeap {
+	h := BlockHeap{impl: &downHeap{}}
+	heap.Init(h.impl)
+	return h
+}
+
+// NewUpHeap initializes and returns a new BlockHeap
+func NewUpHeap() BlockHeap {
+	h := BlockHeap{impl: &upHeap{}}
 	heap.Init(h.impl)
 	return h
 }
@@ -54,6 +75,13 @@ func (bh BlockHeap) Push(block *blockNode) {
 	heap.Push(bh.impl, block)
 }
 
+// pushSet pushes a blockset to the heap.
+func (bh BlockHeap) pushSet(bs blockSet) {
+	for _, block := range bs {
+		heap.Push(bh.impl, block)
+	}
+}
+
 // Len returns the length of this heap
 func (bh BlockHeap) Len() int {
 	return bh.impl.Len()
diff --git a/blockdag/blockheap_test.go b/blockdag/blockheap_test.go
index 0f1c77d13..cd10e4f88 100644
--- a/blockdag/blockheap_test.go
+++ b/blockdag/blockheap_test.go
@@ -19,72 +19,102 @@ func TestBlockHeap(t *testing.T) {
 	block0smallHash.hash = daghash.Hash{}
 
 	tests := []struct {
-		name           string
-		toPush         []*blockNode
-		expectedLength int
-		expectedPop    *blockNode
+		name            string
+		toPush          []*blockNode
+		expectedLength  int
+		expectedPopUp   *blockNode
+		expectedPopDown *blockNode
 	}{
 		{
-			name:           "empty heap must have length 0",
-			toPush:         []*blockNode{},
-			expectedLength: 0,
-			expectedPop:    nil,
+			name:            "empty heap must have length 0",
+			toPush:          []*blockNode{},
+			expectedLength:  0,
+			expectedPopDown: nil,
+			expectedPopUp:   nil,
 		},
 		{
-			name:           "heap with one push must have length 1",
-			toPush:         []*blockNode{block0},
-			expectedLength: 1,
-			expectedPop:    nil,
+			name:            "heap with one push must have length 1",
+			toPush:          []*blockNode{block0},
+			expectedLength:  1,
+			expectedPopDown: nil,
+			expectedPopUp:   nil,
 		},
 		{
-			name:           "heap with one push and one pop",
-			toPush:         []*blockNode{block0},
-			expectedLength: 0,
-			expectedPop:    block0,
+			name:            "heap with one push and one pop",
+			toPush:          []*blockNode{block0},
+			expectedLength:  0,
+			expectedPopDown: block0,
+			expectedPopUp:   block0,
 		},
 		{
-			name:           "push two blocks with different heights, heap shouldn't have to rebalance",
-			toPush:         []*blockNode{block100000, block0},
-			expectedLength: 1,
-			expectedPop:    block100000,
+			name: "push two blocks with different heights, heap shouldn't have to rebalance " +
+				"for down direction, but will have to rebalance for up direction",
+			toPush:          []*blockNode{block100000, block0},
+			expectedLength:  1,
+			expectedPopDown: block100000,
+			expectedPopUp:   block0,
 		},
 		{
-			name:           "push two blocks with different heights, heap must rebalance",
-			toPush:         []*blockNode{block0, block100000},
-			expectedLength: 1,
-			expectedPop:    block100000,
+			name: "push two blocks with different heights, heap shouldn't have to rebalance " +
+				"for up direction, but will have to rebalance for down direction",
+			toPush:          []*blockNode{block0, block100000},
+			expectedLength:  1,
+			expectedPopDown: block100000,
+			expectedPopUp:   block0,
 		},
 		{
-			name:           "push two blocks with equal heights but different hashes, heap shouldn't have to rebalance",
-			toPush:         []*blockNode{block0, block0smallHash},
-			expectedLength: 1,
-			expectedPop:    block0,
+			name: "push two blocks with equal heights but different hashes, heap shouldn't have to rebalance " +
+				"for down direction, but will have to rebalance for up direction",
+			toPush:          []*blockNode{block0, block0smallHash},
+			expectedLength:  1,
+			expectedPopDown: block0,
+			expectedPopUp:   block0smallHash,
 		},
 		{
-			name:           "push two blocks with equal heights but different hashes, heap must rebalance",
-			toPush:         []*blockNode{block0smallHash, block0},
-			expectedLength: 1,
-			expectedPop:    block0,
+			name: "push two blocks with equal heights but different hashes, heap shouldn't have to rebalance " +
+				"for up direction, but will have to rebalance for down direction",
+			toPush:          []*blockNode{block0smallHash, block0},
+			expectedLength:  1,
+			expectedPopDown: block0,
+			expectedPopUp:   block0smallHash,
 		},
 	}
 
 	for _, test := range tests {
-		heap := NewHeap()
+		dHeap := NewDownHeap()
 		for _, block := range test.toPush {
-			heap.Push(block)
+			dHeap.Push(block)
 		}
 
 		var poppedBlock *blockNode
-		if test.expectedPop != nil {
-			poppedBlock = heap.pop()
+		if test.expectedPopDown != nil {
+			poppedBlock = dHeap.pop()
 		}
-		if heap.Len() != test.expectedLength {
-			t.Errorf("unexpected heap length in test \"%s\". "+
-				"Expected: %v, got: %v", test.name, test.expectedLength, heap.Len())
+		if dHeap.Len() != test.expectedLength {
+			t.Errorf("unexpected down heap length in test \"%s\". "+
+				"Expected: %v, got: %v", test.name, test.expectedLength, dHeap.Len())
 		}
-		if poppedBlock != test.expectedPop {
-			t.Errorf("unexpected popped block in test \"%s\". "+
-				"Expected: %v, got: %v", test.name, test.expectedPop, poppedBlock)
+		if poppedBlock != test.expectedPopDown {
+			t.Errorf("unexpected popped block for down heap in test \"%s\". "+
+				"Expected: %v, got: %v", test.name, test.expectedPopDown, poppedBlock)
+		}
+
+		uHeap := NewUpHeap()
+		for _, block := range test.toPush {
+			uHeap.Push(block)
+		}
+
+		poppedBlock = nil
+		if test.expectedPopUp != nil {
+			poppedBlock = uHeap.pop()
+		}
+		if uHeap.Len() != test.expectedLength {
+			t.Errorf("unexpected up heap length in test \"%s\". "+
+				"Expected: %v, got: %v", test.name, test.expectedLength, uHeap.Len())
+		}
+		if poppedBlock != test.expectedPopUp {
+			t.Errorf("unexpected popped block for up heap in test \"%s\". "+
+				"Expected: %v, got: %v", test.name, test.expectedPopDown, poppedBlock)
 		}
 	}
 }
diff --git a/blockdag/dag.go b/blockdag/dag.go
index a45b57110..6495ae38b 100644
--- a/blockdag/dag.go
+++ b/blockdag/dag.go
@@ -158,7 +158,7 @@ type BlockDAG struct {
 //
 // This function is safe for concurrent access.
 func (dag *BlockDAG) HaveBlock(hash *daghash.Hash) (bool, error) {
-	exists, err := dag.blockExists(hash)
+	exists, err := dag.BlockExists(hash)
 	if err != nil {
 		return false, err
 	}
@@ -204,30 +204,41 @@ func (dag *BlockDAG) IsKnownOrphan(hash *daghash.Hash) bool {
 	return exists
 }
 
-// GetOrphanRoot returns the head of the chain for the provided hash from the
-// map of orphan blocks.
+// GetOrphanMissingAncestorHashes returns all of the missing parents in the orphan's sub-DAG
 //
 // This function is safe for concurrent access.
-func (dag *BlockDAG) GetOrphanRoot(hash *daghash.Hash) *daghash.Hash {
+func (dag *BlockDAG) GetOrphanMissingAncestorHashes(hash *daghash.Hash) ([]*daghash.Hash, error) {
 	// Protect concurrent access.  Using a read lock only so multiple
 	// readers can query without blocking each other.
 	dag.orphanLock.RLock()
 	defer dag.orphanLock.RUnlock()
 
-	// Keep looping while the parent of each orphaned block is
-	// known and is an orphan itself.
-	orphanRoot := hash
-	parentHash := hash
-	for {
-		orphan, exists := dag.orphans[*parentHash]
-		if !exists {
-			break
-		}
-		orphanRoot = parentHash
-		parentHash = orphan.block.MsgBlock().Header.SelectedParentHash()
-	}
+	missingAncestorsHashes := make([]*daghash.Hash, 0)
 
-	return orphanRoot
+	visited := make(map[daghash.Hash]bool)
+	queue := []*daghash.Hash{hash}
+	for len(queue) > 0 {
+		var current *daghash.Hash
+		current, queue = queue[0], queue[1:]
+		if !visited[*current] {
+			visited[*current] = true
+			orphan, orphanExists := dag.orphans[*current]
+			if orphanExists {
+				for _, parentHash := range orphan.block.MsgBlock().Header.ParentHashes {
+					queue = append(queue, &parentHash)
+				}
+			} else {
+				existsInDag, err := dag.BlockExists(current)
+				if err != nil {
+					return nil, err
+				}
+				if !existsInDag {
+					missingAncestorsHashes = append(missingAncestorsHashes, current)
+				}
+			}
+		}
+	}
+	return missingAncestorsHashes, nil
 }
 
 // removeOrphanBlock removes the passed orphan block from the orphan pool and
@@ -1037,8 +1048,6 @@ func (dag *BlockDAG) IsCurrent() bool {
 
 // selectedTip returns the current selected tip for the DAG.
 // It will return nil if there is no tip.
-//
-// This function is safe for concurrent access.
 func (dag *BlockDAG) selectedTip() *blockNode {
 	return dag.virtual.selectedParent
 }
@@ -1056,6 +1065,19 @@ func (dag *BlockDAG) SelectedTipHeader() *wire.BlockHeader {
 	return selectedTip.Header()
 }
 
+// SelectedTipHash returns the hash of the current selected tip for the DAG.
+// It will return nil if there is no tip.
+//
+// This function is safe for concurrent access.
+func (dag *BlockDAG) SelectedTipHash() *daghash.Hash {
+	selectedTip := dag.selectedTip()
+	if selectedTip == nil {
+		return nil
+	}
+
+	return &selectedTip.hash
+}
+
 // UTXOSet returns the DAG's UTXO set
 func (dag *BlockDAG) UTXOSet() *FullUTXOSet {
 	return dag.virtual.utxoSet
@@ -1125,19 +1147,26 @@ func (dag *BlockDAG) HeaderByHash(hash *daghash.Hash) (*wire.BlockHeader, error)
 	return node.Header(), nil
 }
 
-// BlockLocatorFromHash returns a block locator for the passed block hash.
+// BlockLocatorFromHash traverses the selected parent chain of the given block hash
+// until it finds a block that exists in the virtual's selected parent chain, and
+// then it returns its block locator.
 // See BlockLocator for details on the algorithm used to create a block locator.
 //
 // In addition to the general algorithm referenced above, this function will
-// return the block locator for the latest known tip of the main (best) chain if
+// return the block locator for the selected tip if
 // the passed hash is not currently known.
 //
 // This function is safe for concurrent access.
 func (dag *BlockDAG) BlockLocatorFromHash(hash *daghash.Hash) BlockLocator {
 	dag.dagLock.RLock()
+	defer dag.dagLock.RUnlock()
 	node := dag.index.LookupNode(hash)
+	if node != nil {
+		for !dag.IsInSelectedPathChain(&node.hash) {
+			node = node.selectedParent
+		}
+	}
 	locator := dag.blockLocator(node)
-	dag.dagLock.RUnlock()
 	return locator
 }
 
@@ -1145,11 +1174,11 @@ func (dag *BlockDAG) BlockLocatorFromHash(hash *daghash.Hash) BlockLocator {
 // main (best) chain.
 //
 // This function is safe for concurrent access.
-func (dag *BlockDAG) LatestBlockLocator() (BlockLocator, error) {
+func (dag *BlockDAG) LatestBlockLocator() BlockLocator {
 	dag.dagLock.RLock()
+	defer dag.dagLock.RUnlock()
 	locator := dag.blockLocator(nil)
-	dag.dagLock.RUnlock()
-	return locator, nil
+	return locator
 }
 
 // blockLocator returns a block locator for the passed block node.  The passed
@@ -1348,24 +1377,16 @@ func (dag *BlockDAG) locateInventory(locator BlockLocator, hashStop *daghash.Has
 		}
 	}
 
-	// Start at the block after the most recently known block.  When there
-	// is no next block it means the most recently known block is the tip of
-	// the best chain, so there is nothing more to do.
-	startNode = startNode.diffChild
-	if startNode == nil {
-		return nil, 0
-	}
-
-	// Calculate how many entries are needed.
-	total := uint32((dag.selectedTip().height - startNode.height) + 1)
+	// Estimate how many entries are needed.
+	estimatedEntries := uint32((dag.selectedTip().blueScore - startNode.blueScore) + 1)
 	if stopNode != nil && stopNode.height >= startNode.height {
-		total = uint32((stopNode.height - startNode.height) + 1)
+		estimatedEntries = uint32((stopNode.blueScore - startNode.blueScore) + 1)
 	}
-	if total > maxEntries {
-		total = maxEntries
+	if estimatedEntries > maxEntries {
+		estimatedEntries = maxEntries
 	}
 
-	return startNode, total
+	return startNode, estimatedEntries
 }
 
 // locateBlocks returns the hashes of the blocks after the first known block in
@@ -1376,23 +1397,47 @@ func (dag *BlockDAG) locateInventory(locator BlockLocator, hashStop *daghash.Has
 //
 // This function MUST be called with the DAG state lock held (for reads).
 func (dag *BlockDAG) locateBlocks(locator BlockLocator, hashStop *daghash.Hash, maxHashes uint32) []daghash.Hash {
-	// Find the node after the first known block in the locator and the
-	// total number of nodes after it needed while respecting the stop hash
-	// and max entries.
-	node, total := dag.locateInventory(locator, hashStop, maxHashes)
-	if total == 0 {
-		return nil
-	}
-
-	// Populate and return the found hashes.
-	hashes := make([]daghash.Hash, 0, total)
-	for i := uint32(0); i < total; i++ {
-		hashes = append(hashes, node.hash)
-		node = node.diffChild
+	nodes := dag.locateBlockNodes(locator, hashStop, maxHashes)
+	hashes := make([]daghash.Hash, len(nodes))
+	for i, node := range nodes {
+		hashes[i] = node.hash
 	}
 	return hashes
 }
 
+func (dag *BlockDAG) locateBlockNodes(locator BlockLocator, hashStop *daghash.Hash, maxEntries uint32) []*blockNode {
+	// Find the first known block in the locator and the
+	// estimated number of nodes after it needed while respecting the stop hash
+	// and max entries.
+	node, estimatedEntries := dag.locateInventory(locator, hashStop, maxEntries)
+	if estimatedEntries == 0 {
+		return nil
+	}
+	stopNode := dag.index.LookupNode(hashStop)
+
+	// Populate and return the found nodes.
+	nodes := make([]*blockNode, 0, estimatedEntries)
+	queue := NewUpHeap()
+	queue.pushSet(node.children)
+
+	visited := newSet()
+	for i := uint32(0); queue.Len() > 0 && i < maxEntries; i++ {
+		var current *blockNode
+		current = queue.pop()
+		if !visited.contains(current) {
+			visited.add(current)
+			isBeforeStop := (stopNode == nil) || (current.height < stopNode.height)
+			if isBeforeStop || current.hash.IsEqual(hashStop) {
+				nodes = append(nodes, current)
+			}
+			if isBeforeStop {
+				queue.pushSet(current.children)
+			}
+		}
+	}
+	return nodes
+}
+
 // LocateBlocks returns the hashes of the blocks after the first known block in
 // the locator until the provided stop hash is reached, or up to the provided
 // max number of block hashes.
@@ -1421,19 +1466,10 @@ func (dag *BlockDAG) LocateBlocks(locator BlockLocator, hashStop *daghash.Hash,
 //
 // This function MUST be called with the DAG state lock held (for reads).
 func (dag *BlockDAG) locateHeaders(locator BlockLocator, hashStop *daghash.Hash, maxHeaders uint32) []*wire.BlockHeader {
-	// Find the node after the first known block in the locator and the
-	// total number of nodes after it needed while respecting the stop hash
-	// and max entries.
-	node, total := dag.locateInventory(locator, hashStop, maxHeaders)
-	if total == 0 {
-		return nil
-	}
-
-	// Populate and return the found headers.
-	headers := make([]*wire.BlockHeader, 0, total)
-	for i := uint32(0); i < total; i++ {
-		headers = append(headers, node.Header())
-		node = node.diffChild
+	nodes := dag.locateBlockNodes(locator, hashStop, maxHeaders)
+	headers := make([]*wire.BlockHeader, len(nodes))
+	for i, node := range nodes {
+		headers[i] = node.Header()
 	}
 	return headers
 }
diff --git a/blockdag/phantom.go b/blockdag/phantom.go
index 453d90352..44ca39af6 100644
--- a/blockdag/phantom.go
+++ b/blockdag/phantom.go
@@ -77,7 +77,7 @@ func blueCandidates(chainStart *blockNode) blockSet {
 func traverseCandidates(newBlock *blockNode, candidates blockSet, selectedParent *blockNode) []*blockNode {
 	blues := []*blockNode{}
 	selectedParentPast := newSet()
-	queue := NewHeap()
+	queue := NewDownHeap()
 	visited := newSet()
 
 	for _, parent := range newBlock.parents {
diff --git a/blockdag/process.go b/blockdag/process.go
index 915603cec..de5bb34a0 100644
--- a/blockdag/process.go
+++ b/blockdag/process.go
@@ -33,11 +33,11 @@ const (
 	BFNone BehaviorFlags = 0
 )
 
-// blockExists determines whether a block with the given hash exists either in
-// the main chain or any side chains.
+// BlockExists determines whether a block with the given hash exists in
+// the DAG.
 //
 // This function is safe for concurrent access.
-func (dag *BlockDAG) blockExists(hash *daghash.Hash) (bool, error) {
+func (dag *BlockDAG) BlockExists(hash *daghash.Hash) (bool, error) {
 	// Check block index first (could be main chain or side chain blocks).
 	if dag.index.HaveBlock(hash) {
 		return true, nil
@@ -148,7 +148,7 @@ func (dag *BlockDAG) ProcessBlock(block *util.Block, flags BehaviorFlags) (bool,
 	log.Tracef("Processing block %s", blockHash)
 
 	// The block must not already exist in the main chain or side chains.
-	exists, err := dag.blockExists(blockHash)
+	exists, err := dag.BlockExists(blockHash)
 	if err != nil {
 		return false, err
 	}
@@ -212,7 +212,7 @@ func (dag *BlockDAG) ProcessBlock(block *util.Block, flags BehaviorFlags) (bool,
 	// Handle orphan blocks.
 	allParentsExist := true
 	for _, parentHash := range blockHeader.ParentHashes {
-		parentExists, err := dag.blockExists(&parentHash)
+		parentExists, err := dag.BlockExists(&parentHash)
 		if err != nil {
 			return false, err
 		}
diff --git a/blockdag/validate.go b/blockdag/validate.go
index 8fce6de39..3a2ea644d 100644
--- a/blockdag/validate.go
+++ b/blockdag/validate.go
@@ -754,7 +754,7 @@ func (dag *BlockDAG) validateDifficulty(header *wire.BlockHeader, bluestParent *
 // validateParents validates that no parent is an ancestor of another parent
 func validateParents(blockHeader *wire.BlockHeader, parents blockSet) error {
 	minHeight := int32(math.MaxInt32)
-	queue := NewHeap()
+	queue := NewDownHeap()
 	visited := newSet()
 	for _, parent := range parents {
 		if parent.height < minHeight {
diff --git a/blockdag/virtualblock_test.go b/blockdag/virtualblock_test.go
index de6b93d71..8c0714453 100644
--- a/blockdag/virtualblock_test.go
+++ b/blockdag/virtualblock_test.go
@@ -32,7 +32,7 @@ func TestVirtualBlock(t *testing.T) {
 	// Set its tips to tipsToSet
 	// Add to it all the tips in tipsToAdd, one after the other
 	// Call .Tips() on it and compare the result to expectedTips
-	// Call .SelectedTip() on it and compare the result to expectedSelectedParent
+	// Call .selectedTip() on it and compare the result to expectedSelectedParent
 	tests := []struct {
 		name                   string
 		tipsToSet              []*blockNode
diff --git a/btcjson/dagsvrresults.go b/btcjson/dagsvrresults.go
index 7f0df5fc8..5f0f2dad9 100644
--- a/btcjson/dagsvrresults.go
+++ b/btcjson/dagsvrresults.go
@@ -229,26 +229,25 @@ type GetNetworkInfoResult struct {
 
 // GetPeerInfoResult models the data returned from the getpeerinfo command.
 type GetPeerInfoResult struct {
-	ID             int32   `json:"id"`
-	Addr           string  `json:"addr"`
-	Services       string  `json:"services"`
-	RelayTxes      bool    `json:"relayTxes"`
-	LastSend       int64   `json:"lastSend"`
-	LastRecv       int64   `json:"lastRecv"`
-	BytesSent      uint64  `json:"bytesSent"`
-	BytesRecv      uint64  `json:"bytesRecv"`
-	ConnTime       int64   `json:"connTime"`
-	TimeOffset     int64   `json:"timeOffset"`
-	PingTime       float64 `json:"pingTime"`
-	PingWait       float64 `json:"pingWait,omitempty"`
-	Version        uint32  `json:"version"`
-	SubVer         string  `json:"subVer"`
-	Inbound        bool    `json:"inbound"`
-	StartingHeight int32   `json:"startingHeight"`
-	CurrentHeight  int32   `json:"currentHeight,omitempty"`
-	BanScore       int32   `json:"banScore"`
-	FeeFilter      int64   `json:"feeFilter"`
-	SyncNode       bool    `json:"syncNode"`
+	ID          int32   `json:"id"`
+	Addr        string  `json:"addr"`
+	Services    string  `json:"services"`
+	RelayTxes   bool    `json:"relayTxes"`
+	LastSend    int64   `json:"lastSend"`
+	LastRecv    int64   `json:"lastRecv"`
+	BytesSent   uint64  `json:"bytesSent"`
+	BytesRecv   uint64  `json:"bytesRecv"`
+	ConnTime    int64   `json:"connTime"`
+	TimeOffset  int64   `json:"timeOffset"`
+	PingTime    float64 `json:"pingTime"`
+	PingWait    float64 `json:"pingWait,omitempty"`
+	Version     uint32  `json:"version"`
+	SubVer      string  `json:"subVer"`
+	Inbound     bool    `json:"inbound"`
+	SelectedTip string  `json:"selectedTip,omitempty"`
+	BanScore    int32   `json:"banScore"`
+	FeeFilter   int64   `json:"feeFilter"`
+	SyncNode    bool    `json:"syncNode"`
 }
 
 // GetRawMempoolVerboseResult models the data returned from the getrawmempool
diff --git a/mining/cpuminer/cpuminer.go b/mining/cpuminer/cpuminer.go
index ca4890046..d1946a019 100644
--- a/mining/cpuminer/cpuminer.go
+++ b/mining/cpuminer/cpuminer.go
@@ -71,6 +71,11 @@ type Config struct {
 	// found blocks to.
 	ConnectedCount func() int32
 
+	// ShouldMineOnGenesis checks if the node is connected to at least one
+	// peer, and at least one of its peers knows of any blocks that were mined
+	// on top of the genesis block.
+	ShouldMineOnGenesis func() bool
+
 	// IsCurrent defines the function to use to obtain whether or not the
 	// block chain is current.  This is used by the automatic persistent
 	// mining routine to determine whether or it should attempt mining.
@@ -309,14 +314,14 @@ out:
 			continue
 		}
 
-		// No point in searching for a solution before the chain is
+		// No point in searching for a solution before the DAG is
 		// synced.  Also, grab the same lock as used for block
 		// submission, since the current block will be changing and
 		// this would otherwise end up building a new block template on
 		// a block that is in the process of becoming stale.
 		m.submitBlockLock.Lock()
 		curHeight := m.g.DAGHeight()
-		if curHeight != 0 && !m.cfg.IsCurrent() {
+		if (curHeight != 0 && !m.cfg.IsCurrent()) || (curHeight == 0 && !m.cfg.ShouldMineOnGenesis()) {
 			m.submitBlockLock.Unlock()
 			time.Sleep(time.Second)
 			continue
diff --git a/netsync/interface.go b/netsync/interface.go
index 80019484a..a3592739d 100644
--- a/netsync/interface.go
+++ b/netsync/interface.go
@@ -7,9 +7,7 @@ package netsync
 import (
 	"github.com/daglabs/btcd/blockdag"
 	"github.com/daglabs/btcd/dagconfig"
-	"github.com/daglabs/btcd/dagconfig/daghash"
 	"github.com/daglabs/btcd/mempool"
-	"github.com/daglabs/btcd/peer"
 	"github.com/daglabs/btcd/util"
 	"github.com/daglabs/btcd/wire"
 )
@@ -20,8 +18,6 @@ import (
 type PeerNotifier interface {
 	AnnounceNewTransactions(newTxs []*mempool.TxDesc)
 
-	UpdatePeerHeights(latestBlkHash *daghash.Hash, latestHeight int32, updateSource *peer.Peer)
-
 	RelayInventory(invVect *wire.InvVect, data interface{})
 
 	TransactionConfirmed(tx *util.Tx)
diff --git a/netsync/manager.go b/netsync/manager.go
index f1c27a9c4..90b6365fa 100644
--- a/netsync/manager.go
+++ b/netsync/manager.go
@@ -131,9 +131,17 @@ type headerNode struct {
 // about a peer.
 type peerSyncState struct {
 	syncCandidate   bool
-	requestQueue    []*wire.InvVect
-	requestedTxns   map[daghash.TxID]struct{}
-	requestedBlocks map[daghash.Hash]struct{}
+	requestQueueMtx sync.Mutex
+	// relayedInvsRequestQueue contains invs of blocks and transactions
+	// which are relayed to our node.
+	relayedInvsRequestQueue []*wire.InvVect
+	// requestQueue contains all of the invs that are not relayed to
+	// us; we get them by requesting them or by manually creating them.
+	requestQueue               []*wire.InvVect
+	relayedInvsRequestQueueSet map[daghash.Hash]struct{}
+	requestQueueSet            map[daghash.Hash]struct{}
+	requestedTxns              map[daghash.TxID]struct{}
+	requestedBlocks            map[daghash.Hash]struct{}
 }
 
 // SyncManager is used to communicate block related messages with peers. The
@@ -230,13 +238,14 @@ func (sm *SyncManager) startSync() {
 			continue
 		}
 
-		// Remove sync candidate peers that are no longer candidates due
-		// to passing their latest known block.  NOTE: The < is
-		// intentional as opposed to <=.  While technically the peer
-		// doesn't have a later block when it's equal, it will likely
-		// have one soon so it is a reasonable choice.  It also allows
-		// the case where both are at 0 such as during regression test.
-		if peer.LastBlock() < sm.dag.Height() { //TODO: (Ori) This is probably wrong. Done only for compilation
+		isCandidate, err := peer.IsSyncCandidate()
+		if err != nil {
+			log.Errorf("Failed to check if peer %s is"+
+				"a sync candidate: %s", peer, err)
+			return
+		}
+
+		if !isCandidate {
 			state.syncCandidate = false
 			continue
 		}
@@ -253,15 +262,10 @@ func (sm *SyncManager) startSync() {
 		// to send.
 		sm.requestedBlocks = make(map[daghash.Hash]struct{})
 
-		locator, err := sm.dag.LatestBlockLocator()
-		if err != nil {
-			log.Errorf("Failed to get block locator for the "+
-				"latest block: %s", err)
-			return
-		}
+		locator := sm.dag.LatestBlockLocator()
 
-		log.Infof("Syncing to block height %d from peer %s",
-			bestPeer.LastBlock(), bestPeer.Addr())
+		log.Infof("Syncing to block %s from peer %s",
+			bestPeer.SelectedTip(), bestPeer.Addr())
 
 		// When the current height is less than a known checkpoint we
 		// can use block headers to learn about which blocks comprise
@@ -342,9 +346,11 @@ func (sm *SyncManager) handleNewPeerMsg(peer *peerpkg.Peer) {
 	// Initialize the peer state
 	isSyncCandidate := sm.isSyncCandidate(peer)
 	sm.peerStates[peer] = &peerSyncState{
-		syncCandidate:   isSyncCandidate,
-		requestedTxns:   make(map[daghash.TxID]struct{}),
-		requestedBlocks: make(map[daghash.Hash]struct{}),
+		syncCandidate:              isSyncCandidate,
+		requestedTxns:              make(map[daghash.TxID]struct{}),
+		requestedBlocks:            make(map[daghash.Hash]struct{}),
+		requestQueueSet:            make(map[daghash.Hash]struct{}),
+		relayedInvsRequestQueueSet: make(map[daghash.Hash]struct{}),
 	}
 
 	// Start syncing by choosing the best candidate if needed.
@@ -466,22 +472,26 @@ func (sm *SyncManager) handleTxMsg(tmsg *txMsg) {
 // current returns true if we believe we are synced with our peers, false if we
 // still have blocks to check
 func (sm *SyncManager) current() bool {
-	if !sm.dag.IsCurrent() {
-		return false
-	}
+	return sm.dag.IsCurrent()
+}
 
-	// if blockChain thinks we are current and we have no syncPeer it
-	// is probably right.
-	if sm.syncPeer == nil {
-		return true
+// restartSyncIfNeeded finds a new sync candidate if we're not expecting any
+// blocks from the current one.
+func (sm *SyncManager) restartSyncIfNeeded() {
+	if sm.syncPeer != nil {
+		syncPeerState, exists := sm.peerStates[sm.syncPeer]
+		if exists {
+			isWaitingForBlocks := func() bool {
+				syncPeerState.requestQueueMtx.Lock()
+				defer syncPeerState.requestQueueMtx.Unlock()
+				return len(syncPeerState.requestedBlocks) != 0 || len(syncPeerState.requestQueue) != 0
+			}()
+			if isWaitingForBlocks {
+				return
+			}
+		}
 	}
-
-	// No matter what chain thinks, if we are below the block we are syncing
-	// to we are not current.
-	if sm.dag.Height() < sm.syncPeer.LastBlock() { //TODO: (Ori) This is probably wrong. Done only for compilation
-		return false
-	}
-	return true
+	sm.startSync()
 }
 
 // handleBlockMsg handles block messages from all peers.
@@ -533,14 +543,17 @@ func (sm *SyncManager) handleBlockMsg(bmsg *blockMsg) {
 		}
 	}
 
-	// Remove block from request maps. Either chain will know about it and
-	// so we shouldn't have any more instances of trying to fetch it, or we
-	// will fail the insert and thus we'll retry next time we get an inv.
+	// Process the block to include validation, orphan handling, etc.
+	isOrphan, err := sm.dag.ProcessBlock(bmsg.block, behaviorFlags)
+
+	// Remove block from request maps. Either DAG knows about it and
+	// so we shouldn't have any more instances of trying to fetch it, or
+	// the insertion fails and thus we'll retry next time we get an inv.
 	delete(state.requestedBlocks, *blockHash)
 	delete(sm.requestedBlocks, *blockHash)
 
-	// Process the block to include validation, orphan handling, etc.
-	isOrphan, err := sm.dag.ProcessBlock(bmsg.block, behaviorFlags)
+	sm.restartSyncIfNeeded()
+
 	if err != nil {
 		// When the error is a rule error, it means the block was simply
 		// rejected as opposed to something actually going wrong, so log
@@ -565,69 +578,32 @@ func (sm *SyncManager) handleBlockMsg(bmsg *blockMsg) {
 		return
 	}
 
-	// Meta-data about the new block this peer is reporting. We use this
-	// below to update this peer's lastest block height and the heights of
-	// other peers based on their last announced block hash. This allows us
-	// to dynamically update the block heights of peers, avoiding stale
-	// heights when looking for a new sync peer. Upon acceptance of a block
-	// or recognition of an orphan, we also use this information to update
-	// the block heights over other peers who's invs may have been ignored
-	// if we are actively syncing while the chain is not yet current or
-	// who may have lost the lock announcment race.
-	var heightUpdate int32
-	var blkHashUpdate *daghash.Hash
-
 	// Request the parents for the orphan block from the peer that sent it.
 	if isOrphan {
-		// We've just received an orphan block from a peer. In order
-		// to update the height of the peer, we try to extract the
-		// block height from the scriptSig of the coinbase transaction.
-		// Extraction is only attempted if the block's version is
-		// high enough (ver 2+).
-		coinbaseTx := bmsg.block.Transactions()[0]
-		cbHeight, err := blockdag.ExtractCoinbaseHeight(coinbaseTx)
+		missingAncestors, err := sm.dag.GetOrphanMissingAncestorHashes(blockHash)
 		if err != nil {
-			log.Warnf("Unable to extract height from "+
-				"coinbase tx: %s", err)
-		} else {
-			log.Debugf("Extracted height of %d from "+
-				"orphan block", cbHeight)
-			heightUpdate = cbHeight
-			blkHashUpdate = blockHash
-		}
-
-		orphanRoot := sm.dag.GetOrphanRoot(blockHash)
-		locator, err := sm.dag.LatestBlockLocator()
-		if err != nil {
-			log.Warnf("Failed to get block locator for the "+
-				"latest block: %s", err)
-		} else {
-			peer.PushGetBlocksMsg(locator, orphanRoot)
+			log.Errorf("Failed to find missing ancestors for block %s: %s",
+				blockHash, err)
+			return
 		}
+		sm.addBlocksToRequestQueue(state, missingAncestors, false)
 	} else {
 		// When the block is not an orphan, log information about it and
 		// update the chain state.
 		sm.progressLogger.LogBlockHeight(bmsg.block)
 
-		// Update this peer's latest block height, for future
-		// potential sync node candidacy.
-		highestTipHash := sm.dag.HighestTipHash()
-		heightUpdate = sm.dag.Height() //TODO: (Ori) This is probably wrong. Done only for compilation
-		blkHashUpdate = &highestTipHash
-
 		// Clear the rejected transactions.
 		sm.rejectedTxns = make(map[daghash.TxID]struct{})
 	}
 
-	// Update the block height for this peer. But only send a message to
-	// the server for updating peer heights if this is an orphan or our
-	// chain is "current". This avoids sending a spammy amount of messages
-	// if we're syncing the chain from scratch.
-	if blkHashUpdate != nil && heightUpdate != 0 {
-		peer.UpdateLastBlockHeight(heightUpdate)
-		if isOrphan || sm.current() {
-			go sm.peerNotifier.UpdatePeerHeights(blkHashUpdate, heightUpdate,
-				peer)
+	// We don't want to flood our sync peer with getdata messages, so
+	// instead of asking it immediately about missing ancestors, we first
+	// wait until it finishes to send us all of the requested blocks.
+	if (isOrphan && peer != sm.syncPeer) || (peer == sm.syncPeer && len(state.requestedBlocks) == 0) {
+		err := sm.sendInvsFromRequestQueue(peer, state)
+		if err != nil {
+			log.Errorf("Failed to send invs from queue: %s", err)
+			return
 		}
 	}
 
@@ -683,6 +659,37 @@ func (sm *SyncManager) handleBlockMsg(bmsg *blockMsg) {
 	}
 }
 
+func (sm *SyncManager) addBlocksToRequestQueue(state *peerSyncState, hashes []*daghash.Hash, isRelayedInv bool) {
+	state.requestQueueMtx.Lock()
+	defer state.requestQueueMtx.Unlock()
+	for _, hash := range hashes {
+		if _, exists := sm.requestedBlocks[*hash]; !exists {
+			iv := wire.NewInvVect(wire.InvTypeBlock, hash)
+			state.addInvToRequestQueue(iv, isRelayedInv)
+		}
+	}
+}
+
+func (state *peerSyncState) addInvToRequestQueue(iv *wire.InvVect, isRelayedInv bool) {
+	if isRelayedInv {
+		if _, exists := state.relayedInvsRequestQueueSet[iv.Hash]; !exists {
+			state.relayedInvsRequestQueueSet[iv.Hash] = struct{}{}
+			state.relayedInvsRequestQueue = append(state.relayedInvsRequestQueue, iv)
+		}
+	} else {
+		if _, exists := state.requestQueueSet[iv.Hash]; !exists {
+			state.requestQueueSet[iv.Hash] = struct{}{}
+			state.requestQueue = append(state.requestQueue, iv)
+		}
+	}
+}
+
+func (state *peerSyncState) addInvToRequestQueueWithLock(iv *wire.InvVect, isRelayedInv bool) {
+	state.requestQueueMtx.Lock()
+	defer state.requestQueueMtx.Unlock()
+	state.addInvToRequestQueue(iv, isRelayedInv)
+}
+
 // fetchHeaderBlocks creates and sends a request to the syncPeer for the next
 // list of blocks to be downloaded based on the current list of headers.
 func (sm *SyncManager) fetchHeaderBlocks() {
@@ -845,9 +852,10 @@ func (sm *SyncManager) handleHeadersMsg(hmsg *headersMsg) {
 // are in the memory pool (either the main pool or orphan pool).
 func (sm *SyncManager) haveInventory(invVect *wire.InvVect) (bool, error) {
 	switch invVect.Type {
+	case wire.InvTypeSyncBlock:
+		fallthrough
 	case wire.InvTypeBlock:
-		// Ask chain if the block is known to it in any form (main
-		// chain, side chain, or orphan).
+		// Ask DAG if the block is known to it in any form (in DAG or as an orphan).
 		return sm.dag.HaveBlock(&invVect.Hash)
 
 	case wire.InvTypeTx:
@@ -900,30 +908,12 @@ func (sm *SyncManager) handleInvMsg(imsg *invMsg) {
 	lastBlock := -1
 	invVects := imsg.inv.InvList
 	for i := len(invVects) - 1; i >= 0; i-- {
-		if invVects[i].Type == wire.InvTypeBlock {
+		if invVects[i].IsBlockOrSyncBlock() {
 			lastBlock = i
 			break
 		}
 	}
 
-	// If this inv contains a block announcement, and this isn't coming from
-	// our current sync peer or we're current, then update the last
-	// announced block for this peer. We'll use this information later to
-	// update the heights of peers based on blocks we've accepted that they
-	// previously announced.
-	if lastBlock != -1 && (peer != sm.syncPeer || sm.current()) {
-		peer.UpdateLastAnnouncedBlock(&invVects[lastBlock].Hash)
-	}
-
-	// If our chain is current and a peer announces a block we already
-	// know of, then update their current block height.
-	if lastBlock != -1 && sm.current() {
-		blkHeight, err := sm.dag.BlockHeightByHash(&invVects[lastBlock].Hash)
-		if err == nil {
-			peer.UpdateLastBlockHeight(blkHeight)
-		}
-	}
-
 	// Request the advertised inventory if we don't already have it.  Also,
 	// request parent blocks of orphans if we receive one we already have.
 	// Finally, attempt to detect potential stalls due to long side chains
@@ -932,6 +922,7 @@ func (sm *SyncManager) handleInvMsg(imsg *invMsg) {
 		// Ignore unsupported inventory types.
 		switch iv.Type {
 		case wire.InvTypeBlock:
+		case wire.InvTypeSyncBlock:
 		case wire.InvTypeTx:
 		default:
 			continue
@@ -964,11 +955,11 @@ func (sm *SyncManager) handleInvMsg(imsg *invMsg) {
 			}
 
 			// Add it to the request queue.
-			state.requestQueue = append(state.requestQueue, iv)
+			state.addInvToRequestQueueWithLock(iv, iv.Type != wire.InvTypeSyncBlock)
 			continue
 		}
 
-		if iv.Type == wire.InvTypeBlock {
+		if iv.IsBlockOrSyncBlock() {
 			// The block is an orphan block that we already have.
 			// When the existing orphan was processed, it requested
 			// the missing parent blocks.  When this scenario
@@ -980,27 +971,23 @@ func (sm *SyncManager) handleInvMsg(imsg *invMsg) {
 			// to signal there are more missing blocks that need to
 			// be requested.
 			if sm.dag.IsKnownOrphan(&iv.Hash) {
-				// Request blocks starting at the latest known
-				// up to the root of the orphan that just came
-				// in.
-				orphanRoot := sm.dag.GetOrphanRoot(&iv.Hash)
-				locator, err := sm.dag.LatestBlockLocator()
+				missingAncestors, err := sm.dag.GetOrphanMissingAncestorHashes(&iv.Hash)
 				if err != nil {
-					log.Errorf("PEER: Failed to get block "+
-						"locator for the latest block: "+
-						"%s", err)
-					continue
+					log.Errorf("Failed to find missing ancestors for block %s: %s",
+						iv.Hash, err)
+					return
 				}
-				peer.PushGetBlocksMsg(locator, orphanRoot)
+				sm.addBlocksToRequestQueue(state, missingAncestors, iv.Type != wire.InvTypeSyncBlock)
 				continue
 			}
 
 			// We already have the final block advertised by this
 			// inventory message, so force a request for more.  This
-			// should only happen if we're on a really long side
-			// chain.
-			if i == lastBlock {
-				// Request blocks after this one up to the
+			// should only happen if our DAG and the peer's DAG have
+			// diverged long time ago.
+			if i == lastBlock && peer == sm.syncPeer {
+				// Request blocks after the first block's ancestor that exists
+				// in the selected path chain, one up to the
 				// final one the remote peer knows about (zero
 				// stop hash).
 				locator := sm.dag.BlockLocatorFromHash(&iv.Hash)
@@ -1009,30 +996,58 @@ func (sm *SyncManager) handleInvMsg(imsg *invMsg) {
 		}
 	}
 
-	// Request as much as possible at once.  Anything that won't fit into
-	// the request will be requested on the next inv message.
-	numRequested := 0
-	gdmsg := wire.NewMsgGetData()
-	requestQueue := state.requestQueue
+	err := sm.sendInvsFromRequestQueue(peer, state)
+	if err != nil {
+		log.Errorf("Failed to send invs from queue: %s", err)
+	}
+}
+
+func (sm *SyncManager) addInvsToGetDataMessageFromQueue(gdmsg *wire.MsgGetData, state *peerSyncState, requestQueue []*wire.InvVect) ([]*wire.InvVect, error) {
+	var invsNum int
+	leftSpaceInGdmsg := wire.MaxInvPerMsg - len(gdmsg.InvList)
+	if len(requestQueue) > leftSpaceInGdmsg {
+		invsNum = leftSpaceInGdmsg
+	} else {
+		invsNum = len(requestQueue)
+	}
+	invsToAdd := make([]*wire.InvVect, 0, invsNum)
+
 	for len(requestQueue) != 0 {
 		iv := requestQueue[0]
 		requestQueue[0] = nil
 		requestQueue = requestQueue[1:]
 
-		switch iv.Type {
-		case wire.InvTypeBlock:
-			// Request the block if there is not already a pending
-			// request.
-			if _, exists := sm.requestedBlocks[iv.Hash]; !exists {
-				sm.requestedBlocks[iv.Hash] = struct{}{}
-				sm.limitHashMap(sm.requestedBlocks, maxRequestedBlocks)
-				state.requestedBlocks[iv.Hash] = struct{}{}
+		exists, err := sm.haveInventory(iv)
+		if err != nil {
+			return nil, err
+		}
+		if !exists {
+			invsToAdd = append(invsToAdd, iv)
+		}
+	}
 
-				gdmsg.AddInvVect(iv)
-				numRequested++
-			}
+	addBlockInv := func(iv *wire.InvVect) {
+		// Request the block if there is not already a pending
+		// request.
+		if _, exists := sm.requestedBlocks[iv.Hash]; !exists {
+			sm.requestedBlocks[iv.Hash] = struct{}{}
+			sm.limitHashMap(sm.requestedBlocks, maxRequestedBlocks)
+			state.requestedBlocks[iv.Hash] = struct{}{}
+
+			gdmsg.AddInvVect(iv)
+		}
+	}
+	for _, iv := range invsToAdd {
+		switch iv.Type {
+		case wire.InvTypeSyncBlock:
+			delete(state.requestQueueSet, iv.Hash)
+			addBlockInv(iv)
+		case wire.InvTypeBlock:
+			delete(state.relayedInvsRequestQueueSet, iv.Hash)
+			addBlockInv(iv)
 
 		case wire.InvTypeTx:
+			delete(state.relayedInvsRequestQueueSet, iv.Hash)
 			// Request the transaction if there is not already a
 			// pending request.
 			if _, exists := sm.requestedTxns[daghash.TxID(iv.Hash)]; !exists {
@@ -1041,18 +1056,36 @@ func (sm *SyncManager) handleInvMsg(imsg *invMsg) {
 				state.requestedTxns[daghash.TxID(iv.Hash)] = struct{}{}
 
 				gdmsg.AddInvVect(iv)
-				numRequested++
 			}
 		}
 
-		if numRequested >= wire.MaxInvPerMsg {
+		if len(requestQueue) >= wire.MaxInvPerMsg {
 			break
 		}
 	}
-	state.requestQueue = requestQueue
+	return requestQueue, nil
+}
+
+func (sm *SyncManager) sendInvsFromRequestQueue(peer *peerpkg.Peer, state *peerSyncState) error {
+	state.requestQueueMtx.Lock()
+	defer state.requestQueueMtx.Unlock()
+	gdmsg := wire.NewMsgGetData()
+	newRequestQueue, err := sm.addInvsToGetDataMessageFromQueue(gdmsg, state, state.requestQueue)
+	if err != nil {
+		return err
+	}
+	state.requestQueue = newRequestQueue
+	if sm.current() {
+		newRequestQueue, err := sm.addInvsToGetDataMessageFromQueue(gdmsg, state, state.relayedInvsRequestQueue)
+		if err != nil {
+			return err
+		}
+		state.relayedInvsRequestQueue = newRequestQueue
+	}
 	if len(gdmsg.InvList) > 0 {
 		peer.QueueMessage(gdmsg, nil)
 	}
+	return nil
 }
 
 // limitTxIDMap is a helper function for maps that require a maximum limit by
diff --git a/peer/example_test.go b/peer/example_test.go
index 894ffa3c9..ae2e0ad08 100644
--- a/peer/example_test.go
+++ b/peer/example_test.go
@@ -25,6 +25,7 @@ func mockRemotePeer() error {
 		UserAgentVersion: "1.0.0", // User agent version to advertise.
 		DAGParams:        &dagconfig.SimNetParams,
 		SubnetworkID:     subnetworkid.SubnetworkIDSupportsAll,
+		SelectedTip:      fakeSelectedTipFn,
 	}
 
 	// Accept connections on the simnet port.
@@ -80,6 +81,7 @@ func Example_newOutboundPeer() {
 			},
 		},
 		SubnetworkID: subnetworkid.SubnetworkIDSupportsAll,
+		SelectedTip:  fakeSelectedTipFn,
 	}
 	p, err := peer.NewOutboundPeer(peerCfg, "127.0.0.1:18555")
 	if err != nil {
diff --git a/peer/log.go b/peer/log.go
index 16be368bc..a9f3b7b79 100644
--- a/peer/log.go
+++ b/peer/log.go
@@ -74,6 +74,8 @@ func invSummary(invList []*wire.InvVect) string {
 			return fmt.Sprintf("error %s", iv.Hash)
 		case wire.InvTypeBlock:
 			return fmt.Sprintf("block %s", iv.Hash)
+		case wire.InvTypeSyncBlock:
+			return fmt.Sprintf("sync block %s", iv.Hash)
 		case wire.InvTypeTx:
 			return fmt.Sprintf("tx %s", iv.Hash)
 		}
@@ -124,8 +126,8 @@ func sanitizeString(str string, maxLength uint) string {
 func messageSummary(msg wire.Message) string {
 	switch msg := msg.(type) {
 	case *wire.MsgVersion:
-		return fmt.Sprintf("agent %s, pver %d, block %d",
-			msg.UserAgent, msg.ProtocolVersion, msg.LastBlock)
+		return fmt.Sprintf("agent %s, pver %d, selected tip %s",
+			msg.UserAgent, msg.ProtocolVersion, msg.SelectedTip)
 
 	case *wire.MsgVerAck:
 		// No summary.
diff --git a/peer/peer.go b/peer/peer.go
index 2bb7bad05..3695d099d 100644
--- a/peer/peer.go
+++ b/peer/peer.go
@@ -216,12 +216,13 @@ type MessageListeners struct {
 
 // Config is the struct to hold configuration options useful to Peer.
 type Config struct {
-	// NewestBlock specifies a callback which provides the newest block
-	// details to the peer as needed.  This can be nil in which case the
-	// peer will report a block height of 0, however it is good practice for
-	// peers to specify this so their currently best known is accurately
-	// reported.
-	NewestBlock HashFunc
+	// SelectedTip specifies a callback which provides the selected tip
+	// to the peer as needed.
+	SelectedTip func() *daghash.Hash
+
+	// SelectedTip specifies a callback which provides the selected tip
+	// to the peer as needed.
+	BlockExists func(*daghash.Hash) (bool, error)
 
 	// HostToNetAddress returns the netaddress for the given host. This can be
 	// nil in  which case the host will be parsed as an IP address.
@@ -369,8 +370,7 @@ type StatsSnap struct {
 	Version        uint32
 	UserAgent      string
 	Inbound        bool
-	StartingHeight int32
-	LastBlock      int32
+	SelectedTip    *daghash.Hash
 	LastPingNonce  uint64
 	LastPingTime   time.Time
 	LastPingMicros int64
@@ -452,15 +452,13 @@ type Peer struct {
 
 	// These fields keep track of statistics for the peer and are protected
 	// by the statsMtx mutex.
-	statsMtx           sync.RWMutex
-	timeOffset         int64
-	timeConnected      time.Time
-	startingHeight     int32
-	lastBlock          int32
-	lastAnnouncedBlock *daghash.Hash
-	lastPingNonce      uint64    // Set to nonce if we have a pending ping.
-	lastPingTime       time.Time // Time we sent last ping.
-	lastPingMicros     int64     // Time for last ping to return.
+	statsMtx       sync.RWMutex
+	timeOffset     int64
+	timeConnected  time.Time
+	selectedTip    *daghash.Hash
+	lastPingNonce  uint64    // Set to nonce if we have a pending ping.
+	lastPingTime   time.Time // Time we sent last ping.
+	lastPingMicros int64     // Time for last ping to return.
 
 	stallControl  chan stallControlMsg
 	outputQueue   chan outMsg
@@ -481,29 +479,6 @@ func (p *Peer) String() string {
 	return fmt.Sprintf("%s (%s)", p.addr, logger.DirectionString(p.inbound))
 }
 
-// UpdateLastBlockHeight updates the last known block for the peer.
-//
-// This function is safe for concurrent access.
-func (p *Peer) UpdateLastBlockHeight(newHeight int32) {
-	p.statsMtx.Lock()
-	log.Tracef("Updating last block height of peer %s from %s to %s",
-		p.addr, p.lastBlock, newHeight)
-	p.lastBlock = newHeight
-	p.statsMtx.Unlock()
-}
-
-// UpdateLastAnnouncedBlock updates meta-data about the last block hash this
-// peer is known to have announced.
-//
-// This function is safe for concurrent access.
-func (p *Peer) UpdateLastAnnouncedBlock(blkHash *daghash.Hash) {
-	log.Tracef("Updating last blk for peer %s, %s", p.addr, blkHash)
-
-	p.statsMtx.Lock()
-	p.lastAnnouncedBlock = blkHash
-	p.statsMtx.Unlock()
-}
-
 // AddKnownInventory adds the passed inventory to the cache of known inventory
 // for the peer.
 //
@@ -540,8 +515,7 @@ func (p *Peer) StatsSnapshot() *StatsSnap {
 		TimeOffset:     p.timeOffset,
 		Version:        protocolVersion,
 		Inbound:        p.inbound,
-		StartingHeight: p.startingHeight,
-		LastBlock:      p.lastBlock,
+		SelectedTip:    p.selectedTip,
 		LastPingNonce:  p.lastPingNonce,
 		LastPingMicros: p.lastPingMicros,
 		LastPingTime:   p.lastPingTime,
@@ -620,17 +594,6 @@ func (p *Peer) SubnetworkID() *subnetworkid.SubnetworkID {
 	return subnetworkID
 }
 
-// LastAnnouncedBlock returns the last announced block of the remote peer.
-//
-// This function is safe for concurrent access.
-func (p *Peer) LastAnnouncedBlock() *daghash.Hash {
-	p.statsMtx.RLock()
-	lastAnnouncedBlock := p.lastAnnouncedBlock
-	p.statsMtx.RUnlock()
-
-	return lastAnnouncedBlock
-}
-
 // LastPingNonce returns the last ping nonce of the remote peer.
 //
 // This function is safe for concurrent access.
@@ -699,15 +662,26 @@ func (p *Peer) ProtocolVersion() uint32 {
 	return protocolVersion
 }
 
-// LastBlock returns the last block of the peer.
+// SelectedTip returns the selected tip of the peer.
 //
 // This function is safe for concurrent access.
-func (p *Peer) LastBlock() int32 {
+func (p *Peer) SelectedTip() *daghash.Hash {
 	p.statsMtx.RLock()
-	lastBlock := p.lastBlock
+	selectedTip := p.selectedTip
 	p.statsMtx.RUnlock()
 
-	return lastBlock
+	return selectedTip
+}
+
+// IsSyncCandidate returns whether or not this peer is a sync candidate.
+//
+// This function is safe for concurrent access.
+func (p *Peer) IsSyncCandidate() (bool, error) {
+	exists, err := p.cfg.BlockExists(p.selectedTip)
+	if err != nil {
+		return false, err
+	}
+	return !exists, nil
 }
 
 // LastSend returns the last send time of the peer.
@@ -762,18 +736,6 @@ func (p *Peer) TimeOffset() int64 {
 	return timeOffset
 }
 
-// StartingHeight returns the last known height the peer reported during the
-// initial negotiation phase.
-//
-// This function is safe for concurrent access.
-func (p *Peer) StartingHeight() int32 {
-	p.statsMtx.RLock()
-	startingHeight := p.startingHeight
-	p.statsMtx.RUnlock()
-
-	return startingHeight
-}
-
 // WantsHeaders returns if the peer wants header messages instead of
 // inventory vectors for blocks.
 //
@@ -789,15 +751,7 @@ func (p *Peer) WantsHeaders() bool {
 // localVersionMsg creates a version message that can be used to send to the
 // remote peer.
 func (p *Peer) localVersionMsg() (*wire.MsgVersion, error) {
-	var blockNum int32
-	if p.cfg.NewestBlock != nil {
-		var err error
-		_, blockNum, err = p.cfg.NewestBlock()
-		if err != nil {
-			return nil, err
-		}
-	}
-
+	selectedTip := p.cfg.SelectedTip()
 	theirNA := p.na
 
 	// If we are behind a proxy and the connection comes from the proxy then
@@ -833,7 +787,7 @@ func (p *Peer) localVersionMsg() (*wire.MsgVersion, error) {
 	subnetworkID := p.cfg.SubnetworkID
 
 	// Version message.
-	msg := wire.NewMsgVersion(ourNA, theirNA, nonce, blockNum, subnetworkID)
+	msg := wire.NewMsgVersion(ourNA, theirNA, nonce, selectedTip, subnetworkID)
 	msg.AddUserAgent(p.cfg.UserAgentName, p.cfg.UserAgentVersion,
 		p.cfg.UserAgentComments...)
 
@@ -1057,8 +1011,7 @@ func (p *Peer) handleRemoteVersionMsg(msg *wire.MsgVersion) error {
 	// Updating a bunch of stats including block based stats, and the
 	// peer's time offset.
 	p.statsMtx.Lock()
-	p.lastBlock = msg.LastBlock
-	p.startingHeight = msg.LastBlock
+	p.selectedTip = msg.SelectedTip
 	p.timeOffset = msg.Timestamp.Unix() - time.Now().Unix()
 	p.statsMtx.Unlock()
 
diff --git a/peer/peer_test.go b/peer/peer_test.go
index fc5178c82..a308708aa 100644
--- a/peer/peer_test.go
+++ b/peer/peer_test.go
@@ -101,8 +101,6 @@ type peerStats struct {
 	wantConnected       bool
 	wantVersionKnown    bool
 	wantVerAckReceived  bool
-	wantLastBlock       int32
-	wantStartingHeight  int32
 	wantLastPingTime    time.Time
 	wantLastPingNonce   uint64
 	wantLastPingMicros  int64
@@ -153,11 +151,6 @@ func testPeer(t *testing.T, p *peer.Peer, s peerStats) {
 		return
 	}
 
-	if p.LastBlock() != s.wantLastBlock {
-		t.Errorf("testPeer: wrong LastBlock - got %v, want %v", p.LastBlock(), s.wantLastBlock)
-		return
-	}
-
 	// Allow for a deviation of 1s, as the second may tick when the message is
 	// in transit and the protocol doesn't support any further precision.
 	if p.TimeOffset() != s.wantTimeOffset && p.TimeOffset() != s.wantTimeOffset-1 {
@@ -176,11 +169,6 @@ func testPeer(t *testing.T, p *peer.Peer, s peerStats) {
 		return
 	}
 
-	if p.StartingHeight() != s.wantStartingHeight {
-		t.Errorf("testPeer: wrong StartingHeight - got %v, want %v", p.StartingHeight(), s.wantStartingHeight)
-		return
-	}
-
 	if p.Connected() != s.wantConnected {
 		t.Errorf("testPeer: wrong Connected - got %v, want %v", p.Connected(), s.wantConnected)
 		return
@@ -231,6 +219,7 @@ func TestPeerConnection(t *testing.T) {
 		ProtocolVersion:   wire.ProtocolVersion, // Configure with older version
 		Services:          0,
 		SubnetworkID:      subnetworkid.SubnetworkIDSupportsAll,
+		SelectedTip:       fakeSelectedTipFn,
 	}
 	peer2Cfg := &peer.Config{
 		Listeners:         peer1Cfg.Listeners,
@@ -241,6 +230,7 @@ func TestPeerConnection(t *testing.T) {
 		ProtocolVersion:   wire.ProtocolVersion + 1,
 		Services:          wire.SFNodeNetwork,
 		SubnetworkID:      subnetworkid.SubnetworkIDSupportsAll,
+		SelectedTip:       fakeSelectedTipFn,
 	}
 
 	wantStats1 := peerStats{
@@ -254,8 +244,8 @@ func TestPeerConnection(t *testing.T) {
 		wantLastPingNonce:   uint64(0),
 		wantLastPingMicros:  int64(0),
 		wantTimeOffset:      int64(0),
-		wantBytesSent:       187, // 163 version + 24 verack
-		wantBytesReceived:   187,
+		wantBytesSent:       215, // 191 version + 24 verack
+		wantBytesReceived:   215,
 	}
 	wantStats2 := peerStats{
 		wantUserAgent:       wire.DefaultUserAgent + "peer:1.0(comment)/",
@@ -268,8 +258,8 @@ func TestPeerConnection(t *testing.T) {
 		wantLastPingNonce:   uint64(0),
 		wantLastPingMicros:  int64(0),
 		wantTimeOffset:      int64(0),
-		wantBytesSent:       187, // 163 version + 24 verack
-		wantBytesReceived:   187,
+		wantBytesSent:       215, // 191 version + 24 verack
+		wantBytesReceived:   215,
 	}
 
 	tests := []struct {
@@ -443,6 +433,7 @@ func TestPeerListeners(t *testing.T) {
 		DAGParams:         &dagconfig.MainNetParams,
 		Services:          wire.SFNodeBloom,
 		SubnetworkID:      subnetworkid.SubnetworkIDSupportsAll,
+		SelectedTip:       fakeSelectedTipFn,
 	}
 	inConn, outConn := pipe(
 		&conn{raddr: "10.0.0.1:8333"},
@@ -603,10 +594,9 @@ func TestPeerListeners(t *testing.T) {
 
 // TestOutboundPeer tests that the outbound peer works as expected.
 func TestOutboundPeer(t *testing.T) {
-
 	peerCfg := &peer.Config{
-		NewestBlock: func() (*daghash.Hash, int32, error) {
-			return nil, 0, errors.New("newest block not found")
+		SelectedTip: func() *daghash.Hash {
+			return &daghash.ZeroHash
 		},
 		UserAgentName:     "peer",
 		UserAgentVersion:  "1.0",
@@ -628,23 +618,7 @@ func TestOutboundPeer(t *testing.T) {
 	// Test trying to connect twice.
 	p.AssociateConnection(c)
 	p.AssociateConnection(c)
-
-	disconnected := make(chan struct{})
-	go func() {
-		p.WaitForDisconnect()
-		disconnected <- struct{}{}
-	}()
-
-	select {
-	case <-disconnected:
-		close(disconnected)
-	case <-time.After(time.Second):
-		t.Fatal("Peer did not automatically disconnect.")
-	}
-
-	if p.Connected() {
-		t.Fatalf("Should not be connected as NewestBlock produces error.")
-	}
+	p.Disconnect()
 
 	// Test Queue Inv
 	fakeBlockHash := &daghash.Hash{0: 0x00, 1: 0x01}
@@ -662,17 +636,17 @@ func TestOutboundPeer(t *testing.T) {
 	<-done
 	p.Disconnect()
 
-	// Test NewestBlock
-	var newestBlock = func() (*daghash.Hash, int32, error) {
+	// Test SelectedTip
+	var selectedTip = func() *daghash.Hash {
 		hashStr := "14a0810ac680a3eb3f82edc878cea25ec41d6b790744e5daeef"
 		hash, err := daghash.NewHashFromStr(hashStr)
 		if err != nil {
-			return nil, 0, err
+			t.Fatalf("daghash.NewHashFromStr: %s", err)
 		}
-		return hash, 234439, nil
+		return hash
 	}
 
-	peerCfg.NewestBlock = newestBlock
+	peerCfg.SelectedTip = selectedTip
 	r1, w1 := io.Pipe()
 	c1 := &conn{raddr: "10.0.0.1:8333", Writer: w1, Reader: r1}
 	p1, err := peer.NewOutboundPeer(peerCfg, "10.0.0.1:8333")
@@ -682,20 +656,6 @@ func TestOutboundPeer(t *testing.T) {
 	}
 	p1.AssociateConnection(c1)
 
-	// Test update latest block
-	latestBlockHash, err := daghash.NewHashFromStr("1a63f9cdff1752e6375c8c76e543a71d239e1a2e5c6db1aa679")
-	if err != nil {
-		t.Errorf("NewHashFromStr: unexpected err %v\n", err)
-		return
-	}
-	p1.UpdateLastAnnouncedBlock(latestBlockHash)
-	p1.UpdateLastBlockHeight(234440)
-	if p1.LastAnnouncedBlock() != latestBlockHash {
-		t.Errorf("LastAnnouncedBlock: wrong block - got %v, want %v",
-			p1.LastAnnouncedBlock(), latestBlockHash)
-		return
-	}
-
 	// Test Queue Inv after connection
 	p1.QueueInventory(fakeInv)
 	p1.Disconnect()
@@ -755,6 +715,7 @@ func TestUnsupportedVersionPeer(t *testing.T) {
 		DAGParams:         &dagconfig.MainNetParams,
 		Services:          0,
 		SubnetworkID:      subnetworkid.SubnetworkIDSupportsAll,
+		SelectedTip:       fakeSelectedTipFn,
 	}
 
 	localNA := wire.NewNetAddressIPPort(
@@ -811,7 +772,7 @@ func TestUnsupportedVersionPeer(t *testing.T) {
 	}
 
 	// Remote peer writes version message advertising invalid protocol version 0
-	invalidVersionMsg := wire.NewMsgVersion(remoteNA, localNA, 0, 0, subnetworkid.SubnetworkIDSupportsAll)
+	invalidVersionMsg := wire.NewMsgVersion(remoteNA, localNA, 0, &daghash.ZeroHash, subnetworkid.SubnetworkIDSupportsAll)
 	invalidVersionMsg.ProtocolVersion = 0
 
 	_, err = wire.WriteMessageN(
@@ -853,3 +814,7 @@ func init() {
 	// Allow self connection when running the tests.
 	peer.TstAllowSelfConns()
 }
+
+func fakeSelectedTipFn() *daghash.Hash {
+	return &daghash.Hash{0x12, 0x34}
+}
diff --git a/server/p2p/p2p.go b/server/p2p/p2p.go
index b63d5abaa..ce39e5cad 100644
--- a/server/p2p/p2p.go
+++ b/server/p2p/p2p.go
@@ -190,24 +190,51 @@ func (ps *peerState) Count() int {
 		len(ps.persistentPeers)
 }
 
-// forAllOutboundPeers is a helper function that runs closure on all outbound
+// forAllOutboundPeers is a helper function that runs a callback on all outbound
 // peers known to peerState.
-func (ps *peerState) forAllOutboundPeers(closure func(sp *Peer)) {
+// The loop stops and returns false if one of the callback calls returns false.
+// Otherwise the function should return true.
+func (ps *peerState) forAllOutboundPeers(callback func(sp *Peer) bool) bool {
 	for _, e := range ps.outboundPeers {
-		closure(e)
+		shouldContinue := callback(e)
+		if !shouldContinue {
+			return false
+		}
 	}
 	for _, e := range ps.persistentPeers {
-		closure(e)
+		shouldContinue := callback(e)
+		if !shouldContinue {
+			return false
+		}
 	}
+	return true
 }
 
-// forAllPeers is a helper function that runs closure on all peers known to
-// peerState.
-func (ps *peerState) forAllPeers(closure func(sp *Peer)) {
+// forAllInboundPeers is a helper function that runs a callback on all inbound
+// peers known to peerState.
+// The loop stops and returns false if one of the callback calls returns false.
+// Otherwise the function should return true.
+func (ps *peerState) forAllInboundPeers(callback func(sp *Peer) bool) bool {
 	for _, e := range ps.inboundPeers {
-		closure(e)
+		shouldContinue := callback(e)
+		if !shouldContinue {
+			return false
+		}
 	}
-	ps.forAllOutboundPeers(closure)
+	return true
+}
+
+// forAllPeers is a helper function that runs a callback on all peers known to
+// peerState.
+// The loop stops and returns false if one of the callback calls returns false.
+// Otherwise the function should return true.
+func (ps *peerState) forAllPeers(callback func(sp *Peer) bool) bool {
+	shouldContinue := ps.forAllInboundPeers(callback)
+	if !shouldContinue {
+		return false
+	}
+	ps.forAllOutboundPeers(callback)
+	return true
 }
 
 // cfHeaderKV is a tuple of a filter header and its associated block hash. The
@@ -243,7 +270,6 @@ type Server struct {
 	Query                chan interface{}
 	relayInv             chan relayMsg
 	broadcast            chan broadcastMsg
-	peerHeightsUpdate    chan updatePeerHeightsMsg
 	wg                   sync.WaitGroup
 	quit                 chan struct{}
 	nat                  serverutils.NAT
@@ -286,11 +312,15 @@ func newServerPeer(s *Server, isPersistent bool) *Peer {
 	}
 }
 
-// newestBlock returns the current best block hash and height using the format
-// required by the configuration for the peer package.
-func (sp *Peer) newestBlock() (*daghash.Hash, int32, error) {
-	highestTipHash := sp.server.DAG.HighestTipHash()
-	return &highestTipHash, sp.server.DAG.Height(), nil //TODO: (Ori) This is probably wrong. Done only for compilation
+// selectedTip returns the current selected tip
+func (sp *Peer) selectedTip() *daghash.Hash {
+	return sp.server.DAG.SelectedTipHash()
+}
+
+// blockExists determines whether a block with the given hash exists in
+// the DAG.
+func (sp *Peer) blockExists(hash *daghash.Hash) (bool, error) {
+	return sp.server.DAG.BlockExists(hash)
 }
 
 // addKnownAddresses adds the given addresses to the set of known addresses to
@@ -617,6 +647,8 @@ func (sp *Peer) OnGetData(_ *peer.Peer, msg *wire.MsgGetData) {
 		switch iv.Type {
 		case wire.InvTypeTx:
 			err = sp.server.pushTxMsg(sp, (*daghash.TxID)(&iv.Hash), c, waitChan)
+		case wire.InvTypeSyncBlock:
+			fallthrough
 		case wire.InvTypeBlock:
 			err = sp.server.pushBlockMsg(sp, &iv.Hash, c, waitChan)
 		case wire.InvTypeFilteredBlock:
@@ -675,7 +707,7 @@ func (sp *Peer) OnGetBlocks(_ *peer.Peer, msg *wire.MsgGetBlocks) {
 	// Generate inventory message.
 	invMsg := wire.NewMsgInv()
 	for i := range hashList {
-		iv := wire.NewInvVect(wire.InvTypeBlock, &hashList[i])
+		iv := wire.NewInvVect(wire.InvTypeSyncBlock, &hashList[i])
 		invMsg.AddInvVect(iv)
 	}
 
@@ -712,8 +744,8 @@ func (sp *Peer) OnGetHeaders(_ *peer.Peer, msg *wire.MsgGetHeaders) {
 	// over with the genesis block if unknown block locators are provided.
 	//
 	// This mirrors the behavior in the reference implementation.
-	chain := sp.server.DAG
-	headers := chain.LocateHeaders(msg.BlockLocatorHashes, &msg.HashStop)
+	dag := sp.server.DAG
+	headers := dag.LocateHeaders(msg.BlockLocatorHashes, &msg.HashStop)
 
 	// Send found headers to the requesting peer.
 	blockHeaders := make([]*wire.BlockHeader, len(headers))
@@ -1381,34 +1413,6 @@ func (s *Server) pushMerkleBlockMsg(sp *Peer, hash *daghash.Hash,
 	return nil
 }
 
-// handleUpdatePeerHeight updates the heights of all peers who were known to
-// announce a block we recently accepted.
-func (s *Server) handleUpdatePeerHeights(state *peerState, umsg updatePeerHeightsMsg) {
-	state.forAllPeers(func(sp *Peer) {
-		// The origin peer should already have the updated height.
-		if sp.Peer == umsg.originPeer {
-			return
-		}
-
-		// This is a pointer to the underlying memory which doesn't
-		// change.
-		latestBlkHash := sp.LastAnnouncedBlock()
-
-		// Skip this peer if it hasn't recently announced any new blocks.
-		if latestBlkHash == nil {
-			return
-		}
-
-		// If the peer has recently announced a block, and this block
-		// matches our newly accepted block, then update their block
-		// height.
-		if *latestBlkHash == *umsg.newHash {
-			sp.UpdateLastBlockHeight(umsg.newHeight)
-			sp.UpdateLastAnnouncedBlock(nil)
-		}
-	})
-}
-
 // handleAddPeerMsg deals with adding new peers.  It is invoked from the
 // peerHandler goroutine.
 func (s *Server) handleAddPeerMsg(state *peerState, sp *Peer) bool {
@@ -1524,9 +1528,9 @@ func (s *Server) handleBanPeerMsg(state *peerState, sp *Peer) {
 // handleRelayInvMsg deals with relaying inventory to peers that are not already
 // known to have it.  It is invoked from the peerHandler goroutine.
 func (s *Server) handleRelayInvMsg(state *peerState, msg relayMsg) {
-	state.forAllPeers(func(sp *Peer) {
+	state.forAllPeers(func(sp *Peer) bool {
 		if !sp.Connected() {
-			return
+			return true
 		}
 
 		// If the inventory is a block and the peer prefers headers,
@@ -1537,23 +1541,23 @@ func (s *Server) handleRelayInvMsg(state *peerState, msg relayMsg) {
 			if !ok {
 				peerLog.Warnf("Underlying data for headers" +
 					" is not a block header")
-				return
+				return true
 			}
 			msgHeaders := wire.NewMsgHeaders()
 			if err := msgHeaders.AddBlockHeader(&blockHeader); err != nil {
 				peerLog.Errorf("Failed to add block"+
 					" header: %s", err)
-				return
+				return true
 			}
 			sp.QueueMessage(msgHeaders, nil)
-			return
+			return true
 		}
 
 		if msg.invVect.Type == wire.InvTypeTx {
 			// Don't relay the transaction to the peer when it has
 			// transaction relaying disabled.
 			if sp.relayTxDisabled() {
-				return
+				return true
 			}
 
 			txD, ok := msg.data.(*mempool.TxDesc)
@@ -1561,28 +1565,28 @@ func (s *Server) handleRelayInvMsg(state *peerState, msg relayMsg) {
 				peerLog.Warnf("Underlying data for tx inv "+
 					"relay is not a *mempool.TxDesc: %T",
 					msg.data)
-				return
+				return true
 			}
 
 			// Don't relay the transaction if the transaction fee-per-kb
 			// is less than the peer's feefilter.
 			feeFilter := uint64(atomic.LoadInt64(&sp.FeeFilterInt))
 			if feeFilter > 0 && txD.FeePerKB < feeFilter {
-				return
+				return true
 			}
 
 			// Don't relay the transaction if there is a bloom
 			// filter loaded and the transaction doesn't match it.
 			if sp.filter.IsLoaded() {
 				if !sp.filter.MatchTxAndUpdate(txD.Tx) {
-					return
+					return true
 				}
 			}
 
 			// Don't relay the transaction if the peer's subnetwork is
 			// incompatible with it.
 			if !txD.Tx.MsgTx().IsSubnetworkCompatible(sp.Peer.SubnetworkID()) {
-				return
+				return true
 			}
 		}
 
@@ -1590,24 +1594,26 @@ func (s *Server) handleRelayInvMsg(state *peerState, msg relayMsg) {
 		// It will be ignored if the peer is already known to
 		// have the inventory.
 		sp.QueueInventory(msg.invVect)
+		return true
 	})
 }
 
 // handleBroadcastMsg deals with broadcasting messages to peers.  It is invoked
 // from the peerHandler goroutine.
 func (s *Server) handleBroadcastMsg(state *peerState, bmsg *broadcastMsg) {
-	state.forAllPeers(func(sp *Peer) {
+	state.forAllPeers(func(sp *Peer) bool {
 		if !sp.Connected() {
-			return
+			return true
 		}
 
 		for _, ep := range bmsg.excludePeers {
 			if sp == ep {
-				return
+				return true
 			}
 		}
 
 		sp.QueueMessage(bmsg.message, nil)
+		return true
 	})
 }
 
@@ -1615,6 +1621,10 @@ type getConnCountMsg struct {
 	reply chan int32
 }
 
+type getShouldMineOnGenesisMsg struct {
+	reply chan bool
+}
+
 //GetPeersMsg is the message type which is used by the rpc server to get the peers list from the p2p server
 type GetPeersMsg struct {
 	Reply chan []*Peer
@@ -1655,20 +1665,36 @@ func (s *Server) handleQuery(state *peerState, querymsg interface{}) {
 	switch msg := querymsg.(type) {
 	case getConnCountMsg:
 		nconnected := int32(0)
-		state.forAllPeers(func(sp *Peer) {
+		state.forAllPeers(func(sp *Peer) bool {
 			if sp.Connected() {
 				nconnected++
 			}
+			return true
 		})
 		msg.reply <- nconnected
 
+	case getShouldMineOnGenesisMsg:
+		shouldMineOnGenesis := true
+		if state.Count() != 0 {
+			shouldMineOnGenesis = state.forAllPeers(func(sp *Peer) bool {
+				if !sp.SelectedTip().IsEqual(s.DAGParams.GenesisHash) {
+					return false
+				}
+				return true
+			})
+		} else {
+			shouldMineOnGenesis = false
+		}
+		msg.reply <- shouldMineOnGenesis
+
 	case GetPeersMsg:
 		peers := make([]*Peer, 0, state.Count())
-		state.forAllPeers(func(sp *Peer) {
+		state.forAllPeers(func(sp *Peer) bool {
 			if !sp.Connected() {
-				return
+				return true
 			}
 			peers = append(peers, sp)
+			return true
 		})
 		msg.Reply <- peers
 
@@ -1816,7 +1842,8 @@ func newPeerConfig(sp *Peer) *peer.Config {
 			// other implementations' alert messages, we will not relay theirs.
 			OnAlert: nil,
 		},
-		NewestBlock:       sp.newestBlock,
+		SelectedTip:       sp.selectedTip,
+		BlockExists:       sp.blockExists,
 		HostToNetAddress:  sp.server.addrManager.HostToNetAddress,
 		Proxy:             config.MainConfig().Proxy,
 		UserAgentName:     userAgentName,
@@ -1937,10 +1964,6 @@ out:
 		case p := <-s.donePeers:
 			s.handleDonePeerMsg(state, p)
 
-		// Block accepted in mainchain or orphan, update peer height.
-		case umsg := <-s.peerHeightsUpdate:
-			s.handleUpdatePeerHeights(state, umsg)
-
 		// Peer to ban.
 		case p := <-s.banPeers:
 			s.handleBanPeerMsg(state, p)
@@ -1959,9 +1982,10 @@ out:
 
 		case <-s.quit:
 			// Disconnect all peers on server shutdown.
-			state.forAllPeers(func(sp *Peer) {
+			state.forAllPeers(func(sp *Peer) bool {
 				srvrLog.Tracef("Shutdown peer %s", sp)
 				sp.Disconnect()
+				return true
 			})
 			break out
 		}
@@ -1978,7 +2002,6 @@ cleanup:
 		select {
 		case <-s.newPeers:
 		case <-s.donePeers:
-		case <-s.peerHeightsUpdate:
 		case <-s.relayInv:
 		case <-s.broadcast:
 		case <-s.Query:
@@ -2024,6 +2047,17 @@ func (s *Server) ConnectedCount() int32 {
 	return <-replyChan
 }
 
+// ShouldMineOnGenesis checks if the node is connected to at least one
+// peer, and at least one of its peers knows of any blocks that were mined
+// on top of the genesis block.
+func (s *Server) ShouldMineOnGenesis() bool {
+	replyChan := make(chan bool)
+
+	s.Query <- getShouldMineOnGenesisMsg{reply: replyChan}
+
+	return <-replyChan
+}
+
 // OutboundGroupCount returns the number of peers connected to the given
 // outbound group key.
 func (s *Server) OutboundGroupCount(key string) int {
@@ -2051,18 +2085,6 @@ func (s *Server) NetTotals() (uint64, uint64) {
 		atomic.LoadUint64(&s.bytesSent)
 }
 
-// UpdatePeerHeights updates the heights of all peers who have have announced
-// the latest connected main chain block, or a recognized orphan. These height
-// updates allow us to dynamically refresh peer heights, ensuring sync peer
-// selection has access to the latest block heights for each peer.
-func (s *Server) UpdatePeerHeights(latestBlkHash *daghash.Hash, latestHeight int32, updateSource *peer.Peer) {
-	s.peerHeightsUpdate <- updatePeerHeightsMsg{
-		newHash:    latestBlkHash,
-		newHeight:  latestHeight,
-		originPeer: updateSource,
-	}
-}
-
 // rebroadcastHandler keeps track of user submitted inventories that we have
 // sent out but have not yet made it into a block. We periodically rebroadcast
 // them in case our peers restarted or otherwise lost track of them.
@@ -2350,7 +2372,6 @@ func NewServer(listenAddrs []string, db database.DB, dagParams *dagconfig.Params
 		broadcast:             make(chan broadcastMsg, config.MainConfig().MaxPeers),
 		quit:                  make(chan struct{}),
 		modifyRebroadcastInv:  make(chan interface{}),
-		peerHeightsUpdate:     make(chan updatePeerHeightsMsg),
 		nat:                   nat,
 		db:                    db,
 		TimeSource:            blockdag.NewMedianTime(),
diff --git a/server/rpc/rpcserver.go b/server/rpc/rpcserver.go
index 926a8ceab..f57533550 100644
--- a/server/rpc/rpcserver.go
+++ b/server/rpc/rpcserver.go
@@ -2450,25 +2450,24 @@ func handleGetPeerInfo(s *Server, cmd interface{}, closeChan <-chan struct{}) (i
 	for _, p := range peers {
 		statsSnap := p.ToPeer().StatsSnapshot()
 		info := &btcjson.GetPeerInfoResult{
-			ID:             statsSnap.ID,
-			Addr:           statsSnap.Addr,
-			Services:       fmt.Sprintf("%08d", uint64(statsSnap.Services)),
-			RelayTxes:      !p.IsTxRelayDisabled(),
-			LastSend:       statsSnap.LastSend.Unix(),
-			LastRecv:       statsSnap.LastRecv.Unix(),
-			BytesSent:      statsSnap.BytesSent,
-			BytesRecv:      statsSnap.BytesRecv,
-			ConnTime:       statsSnap.ConnTime.Unix(),
-			PingTime:       float64(statsSnap.LastPingMicros),
-			TimeOffset:     statsSnap.TimeOffset,
-			Version:        statsSnap.Version,
-			SubVer:         statsSnap.UserAgent,
-			Inbound:        statsSnap.Inbound,
-			StartingHeight: statsSnap.StartingHeight,
-			CurrentHeight:  statsSnap.LastBlock,
-			BanScore:       int32(p.BanScore()),
-			FeeFilter:      p.FeeFilter(),
-			SyncNode:       statsSnap.ID == syncPeerID,
+			ID:          statsSnap.ID,
+			Addr:        statsSnap.Addr,
+			Services:    fmt.Sprintf("%08d", uint64(statsSnap.Services)),
+			RelayTxes:   !p.IsTxRelayDisabled(),
+			LastSend:    statsSnap.LastSend.Unix(),
+			LastRecv:    statsSnap.LastRecv.Unix(),
+			BytesSent:   statsSnap.BytesSent,
+			BytesRecv:   statsSnap.BytesRecv,
+			ConnTime:    statsSnap.ConnTime.Unix(),
+			PingTime:    float64(statsSnap.LastPingMicros),
+			TimeOffset:  statsSnap.TimeOffset,
+			Version:     statsSnap.Version,
+			SubVer:      statsSnap.UserAgent,
+			Inbound:     statsSnap.Inbound,
+			SelectedTip: statsSnap.SelectedTip.String(),
+			BanScore:    int32(p.BanScore()),
+			FeeFilter:   p.FeeFilter(),
+			SyncNode:    statsSnap.ID == syncPeerID,
 		}
 		if p.ToPeer().LastPingNonce() != 0 {
 			wait := float64(time.Since(statsSnap.LastPingTime).Nanoseconds())
diff --git a/server/rpc/rpcserverhelp.go b/server/rpc/rpcserverhelp.go
index 3f82aabcb..e5b58153a 100644
--- a/server/rpc/rpcserverhelp.go
+++ b/server/rpc/rpcserverhelp.go
@@ -450,26 +450,25 @@ var helpDescsEnUS = map[string]string{
 	"getNetTotalsResult-timeMillis":     "Number of milliseconds since 1 Jan 1970 GMT",
 
 	// GetPeerInfoResult help.
-	"getPeerInfoResult-id":             "A unique node ID",
-	"getPeerInfoResult-addr":           "The ip address and port of the peer",
-	"getPeerInfoResult-services":       "Services bitmask which represents the services supported by the peer",
-	"getPeerInfoResult-relayTxes":      "Peer has requested transactions be relayed to it",
-	"getPeerInfoResult-lastSend":       "Time the last message was received in seconds since 1 Jan 1970 GMT",
-	"getPeerInfoResult-lastRecv":       "Time the last message was sent in seconds since 1 Jan 1970 GMT",
-	"getPeerInfoResult-bytesSent":      "Total bytes sent",
-	"getPeerInfoResult-bytesRecv":      "Total bytes received",
-	"getPeerInfoResult-connTime":       "Time the connection was made in seconds since 1 Jan 1970 GMT",
-	"getPeerInfoResult-timeOffset":     "The time offset of the peer",
-	"getPeerInfoResult-pingTime":       "Number of microseconds the last ping took",
-	"getPeerInfoResult-pingWait":       "Number of microseconds a queued ping has been waiting for a response",
-	"getPeerInfoResult-version":        "The protocol version of the peer",
-	"getPeerInfoResult-subVer":         "The user agent of the peer",
-	"getPeerInfoResult-inbound":        "Whether or not the peer is an inbound connection",
-	"getPeerInfoResult-startingHeight": "The latest block height the peer knew about when the connection was established",
-	"getPeerInfoResult-currentHeight":  "The current height of the peer",
-	"getPeerInfoResult-banScore":       "The ban score",
-	"getPeerInfoResult-feeFilter":      "The requested minimum fee a transaction must have to be announced to the peer",
-	"getPeerInfoResult-syncNode":       "Whether or not the peer is the sync peer",
+	"getPeerInfoResult-id":          "A unique node ID",
+	"getPeerInfoResult-addr":        "The ip address and port of the peer",
+	"getPeerInfoResult-services":    "Services bitmask which represents the services supported by the peer",
+	"getPeerInfoResult-relayTxes":   "Peer has requested transactions be relayed to it",
+	"getPeerInfoResult-lastSend":    "Time the last message was received in seconds since 1 Jan 1970 GMT",
+	"getPeerInfoResult-lastRecv":    "Time the last message was sent in seconds since 1 Jan 1970 GMT",
+	"getPeerInfoResult-bytesSent":   "Total bytes sent",
+	"getPeerInfoResult-bytesRecv":   "Total bytes received",
+	"getPeerInfoResult-connTime":    "Time the connection was made in seconds since 1 Jan 1970 GMT",
+	"getPeerInfoResult-timeOffset":  "The time offset of the peer",
+	"getPeerInfoResult-pingTime":    "Number of microseconds the last ping took",
+	"getPeerInfoResult-pingWait":    "Number of microseconds a queued ping has been waiting for a response",
+	"getPeerInfoResult-version":     "The protocol version of the peer",
+	"getPeerInfoResult-subVer":      "The user agent of the peer",
+	"getPeerInfoResult-inbound":     "Whether or not the peer is an inbound connection",
+	"getPeerInfoResult-selectedTip": "The selected tip of the peer",
+	"getPeerInfoResult-banScore":    "The ban score",
+	"getPeerInfoResult-feeFilter":   "The requested minimum fee a transaction must have to be announced to the peer",
+	"getPeerInfoResult-syncNode":    "Whether or not the peer is the sync peer",
 
 	// GetPeerInfoCmd help.
 	"getPeerInfo--synopsis": "Returns data about each connected network peer as an array of json objects.",
diff --git a/server/server.go b/server/server.go
index b3c6e92f9..742778cd9 100644
--- a/server/server.go
+++ b/server/server.go
@@ -114,6 +114,7 @@ func NewServer(listenAddrs []string, db database.DB, dagParams *dagconfig.Params
 		MiningAddrs:            cfg.MiningAddrs,
 		ProcessBlock:           s.p2pServer.SyncManager.ProcessBlock,
 		ConnectedCount:         s.p2pServer.ConnectedCount,
+		ShouldMineOnGenesis:    s.p2pServer.ShouldMineOnGenesis,
 		IsCurrent:              s.p2pServer.SyncManager.IsCurrent,
 	})
 
diff --git a/wire/invvect.go b/wire/invvect.go
index dc755557b..bd1f4337d 100644
--- a/wire/invvect.go
+++ b/wire/invvect.go
@@ -29,6 +29,7 @@ const (
 	InvTypeTx            InvType = 1
 	InvTypeBlock         InvType = 2
 	InvTypeFilteredBlock InvType = 3
+	InvTypeSyncBlock     InvType = 4
 )
 
 // Map of service flags back to their constant names for pretty printing.
@@ -37,6 +38,7 @@ var ivStrings = map[InvType]string{
 	InvTypeTx:            "MSG_TX",
 	InvTypeBlock:         "MSG_BLOCK",
 	InvTypeFilteredBlock: "MSG_FILTERED_BLOCK",
+	InvTypeSyncBlock:     "MSG_SYNC_BLOCK",
 }
 
 // String returns the InvType in human-readable form.
@@ -78,3 +80,8 @@ func writeInvVect(w io.Writer, pver uint32, iv *InvVect) error {
 func (iv *InvVect) String() string {
 	return fmt.Sprintf("{%s:%s}", iv.Type, iv.Hash)
 }
+
+// IsBlockOrSyncBlock returns true if the inv type is InvTypeBlock or InvTypeSyncBlock
+func (iv *InvVect) IsBlockOrSyncBlock() bool {
+	return iv.Type == InvTypeBlock || iv.Type == InvTypeSyncBlock
+}
diff --git a/wire/message_test.go b/wire/message_test.go
index 6ef325032..33613375d 100644
--- a/wire/message_test.go
+++ b/wire/message_test.go
@@ -47,7 +47,7 @@ func TestMessage(t *testing.T) {
 	addrMe := &net.TCPAddr{IP: net.ParseIP("127.0.0.1"), Port: 8333}
 	me := NewNetAddress(addrMe, SFNodeNetwork)
 	me.Timestamp = time.Time{} // Version message has zero value timestamp.
-	msgVersion := NewMsgVersion(me, you, 123123, 0, subnetworkid.SubnetworkIDSupportsAll)
+	msgVersion := NewMsgVersion(me, you, 123123, &daghash.ZeroHash, subnetworkid.SubnetworkIDSupportsAll)
 
 	msgVerack := NewMsgVerAck()
 	msgGetAddr := NewMsgGetAddr(nil)
@@ -87,7 +87,7 @@ func TestMessage(t *testing.T) {
 		btcnet BitcoinNet // Network to use for wire encoding
 		bytes  int        // Expected num bytes read/written
 	}{
-		{msgVersion, msgVersion, pver, MainNet, 145},
+		{msgVersion, msgVersion, pver, MainNet, 173},
 		{msgVerack, msgVerack, pver, MainNet, 24},
 		{msgGetAddr, msgGetAddr, pver, MainNet, 25},
 		{msgAddr, msgAddr, pver, MainNet, 26},
diff --git a/wire/msgversion.go b/wire/msgversion.go
index fc1f3c31f..8458d93db 100644
--- a/wire/msgversion.go
+++ b/wire/msgversion.go
@@ -11,6 +11,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/daglabs/btcd/dagconfig/daghash"
 	"github.com/daglabs/btcd/util/subnetworkid"
 )
 
@@ -52,8 +53,8 @@ type MsgVersion struct {
 	// on the wire.  This has a max length of MaxUserAgentLen.
 	UserAgent string
 
-	// Last block seen by the generator of the version message.
-	LastBlock int32
+	// The selected tip of the generator of the version message.
+	SelectedTip *daghash.Hash
 
 	// Don't announce transactions to peer.
 	DisableRelayTx bool
@@ -104,55 +105,36 @@ func (msg *MsgVersion) BtcDecode(r io.Reader, pver uint32) error {
 		return err
 	}
 
-	// Protocol versions >= 106 added a from address, nonce, and user agent
-	// field and they are only considered present if there are bytes
-	// remaining in the message.
-	if buf.Len() > 0 {
-		err = readNetAddress(buf, pver, &msg.AddrMe, false)
-		if err != nil {
-			return err
-		}
+	err = readNetAddress(buf, pver, &msg.AddrMe, false)
+	if err != nil {
+		return err
 	}
-	if buf.Len() > 0 {
-		err = readElement(buf, &msg.Nonce)
-		if err != nil {
-			return err
-		}
+	err = readElement(buf, &msg.Nonce)
+	if err != nil {
+		return err
 	}
-	if buf.Len() > 0 {
-		userAgent, err := ReadVarString(buf, pver)
-		if err != nil {
-			return err
-		}
-		err = validateUserAgent(userAgent)
-		if err != nil {
-			return err
-		}
-		msg.UserAgent = userAgent
+	userAgent, err := ReadVarString(buf, pver)
+	if err != nil {
+		return err
+	}
+	err = validateUserAgent(userAgent)
+	if err != nil {
+		return err
+	}
+	msg.UserAgent = userAgent
+
+	msg.SelectedTip = &daghash.Hash{}
+	err = readElement(buf, msg.SelectedTip)
+	if err != nil {
+		return err
 	}
 
-	// Protocol versions >= 209 added a last known block field.  It is only
-	// considered present if there are bytes remaining in the message.
-	if buf.Len() > 0 {
-		err = readElement(buf, &msg.LastBlock)
-		if err != nil {
-			return err
-		}
-	}
-
-	// There was no relay transactions field before BIP0037Version, but
-	// the default behavior prior to the addition of the field was to always
-	// relay transactions.
-	if buf.Len() > 0 {
-		// It's safe to ignore the error here since the buffer has at
-		// least one byte and that byte will result in a boolean value
-		// regardless of its value.  Also, the wire encoding for the
-		// field is true when transactions should be relayed, so reverse
-		// it for the DisableRelayTx field.
-		var relayTx bool
-		readElement(r, &relayTx)
-		msg.DisableRelayTx = !relayTx
+	var relayTx bool
+	err = readElement(r, &relayTx)
+	if err != nil {
+		return err
 	}
+	msg.DisableRelayTx = !relayTx
 
 	return nil
 }
@@ -196,7 +178,7 @@ func (msg *MsgVersion) BtcEncode(w io.Writer, pver uint32) error {
 		return err
 	}
 
-	err = writeElement(w, msg.LastBlock)
+	err = writeElement(w, msg.SelectedTip)
 	if err != nil {
 		return err
 	}
@@ -233,7 +215,7 @@ func (msg *MsgVersion) MaxPayloadLength(pver uint32) uint32 {
 // Message interface using the passed parameters and defaults for the remaining
 // fields.
 func NewMsgVersion(me *NetAddress, you *NetAddress, nonce uint64,
-	lastBlock int32, subnetworkID *subnetworkid.SubnetworkID) *MsgVersion {
+	selectedTip *daghash.Hash, subnetworkID *subnetworkid.SubnetworkID) *MsgVersion {
 
 	// Limit the timestamp to one second precision since the protocol
 	// doesn't support better.
@@ -245,7 +227,7 @@ func NewMsgVersion(me *NetAddress, you *NetAddress, nonce uint64,
 		AddrMe:          *me,
 		Nonce:           nonce,
 		UserAgent:       DefaultUserAgent,
-		LastBlock:       lastBlock,
+		SelectedTip:     selectedTip,
 		DisableRelayTx:  false,
 		SubnetworkID:    *subnetworkID,
 	}
diff --git a/wire/msgversion_test.go b/wire/msgversion_test.go
index f927986a9..0986ae9da 100644
--- a/wire/msgversion_test.go
+++ b/wire/msgversion_test.go
@@ -13,6 +13,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/daglabs/btcd/dagconfig/daghash"
 	"github.com/daglabs/btcd/util/random"
 	"github.com/daglabs/btcd/util/subnetworkid"
 	"github.com/davecgh/go-spew/spew"
@@ -23,7 +24,7 @@ func TestVersion(t *testing.T) {
 	pver := ProtocolVersion
 
 	// Create version message data.
-	lastBlock := int32(234234)
+	selectedTip := &daghash.Hash{12, 34}
 	tcpAddrMe := &net.TCPAddr{IP: net.ParseIP("127.0.0.1"), Port: 8333}
 	me := NewNetAddress(tcpAddrMe, SFNodeNetwork)
 	tcpAddrYou := &net.TCPAddr{IP: net.ParseIP("192.168.0.1"), Port: 8333}
@@ -34,7 +35,7 @@ func TestVersion(t *testing.T) {
 	}
 
 	// Ensure we get the correct data back out.
-	msg := NewMsgVersion(me, you, nonce, lastBlock, subnetworkid.SubnetworkIDSupportsAll)
+	msg := NewMsgVersion(me, you, nonce, selectedTip, subnetworkid.SubnetworkIDSupportsAll)
 	if msg.ProtocolVersion != int32(pver) {
 		t.Errorf("NewMsgVersion: wrong protocol version - got %v, want %v",
 			msg.ProtocolVersion, pver)
@@ -55,9 +56,9 @@ func TestVersion(t *testing.T) {
 		t.Errorf("NewMsgVersion: wrong user agent - got %v, want %v",
 			msg.UserAgent, DefaultUserAgent)
 	}
-	if msg.LastBlock != lastBlock {
-		t.Errorf("NewMsgVersion: wrong last block - got %v, want %v",
-			msg.LastBlock, lastBlock)
+	if !msg.SelectedTip.IsEqual(selectedTip) {
+		t.Errorf("NewMsgVersion: wrong selected tip - got %s, want %s",
+			msg.SelectedTip, selectedTip)
 	}
 	if msg.DisableRelayTx {
 		t.Errorf("NewMsgVersion: disable relay tx is not false by "+
@@ -131,13 +132,12 @@ func TestVersion(t *testing.T) {
 // TestVersionWire tests the MsgVersion wire encode and decode for various
 // protocol versions.
 func TestVersionWire(t *testing.T) {
-	// verRelayTxFalse and verRelayTxFalseEncoded is a version message as of
-	// BIP0037Version with the transaction relay disabled.
-	baseVersionBIP0037Copy := *baseVersionBIP0037
-	verRelayTxFalse := &baseVersionBIP0037Copy
+	// verRelayTxFalse and verRelayTxFalseEncoded is a version message with the transaction relay disabled.
+	baseVersionWithRelayTxCopy := *baseVersionWithRelayTx
+	verRelayTxFalse := &baseVersionWithRelayTxCopy
 	verRelayTxFalse.DisableRelayTx = true
-	verRelayTxFalseEncoded := make([]byte, len(baseVersionBIP0037Encoded))
-	copy(verRelayTxFalseEncoded, baseVersionBIP0037Encoded)
+	verRelayTxFalseEncoded := make([]byte, len(baseVersionWithRelayTxEncoded))
+	copy(verRelayTxFalseEncoded, baseVersionWithRelayTxEncoded)
 	verRelayTxFalseEncoded[len(verRelayTxFalseEncoded)-1] = 0
 
 	tests := []struct {
@@ -148,9 +148,15 @@ func TestVersionWire(t *testing.T) {
 	}{
 		// Latest protocol version.
 		{
-			baseVersionBIP0037,
-			baseVersionBIP0037,
-			baseVersionBIP0037Encoded,
+			baseVersionWithRelayTx,
+			baseVersionWithRelayTx,
+			baseVersionWithRelayTxEncoded,
+			ProtocolVersion,
+		},
+		{
+			verRelayTxFalse,
+			verRelayTxFalse,
+			verRelayTxFalseEncoded,
 			ProtocolVersion,
 		},
 	}
@@ -299,107 +305,6 @@ func TestVersionWireErrors(t *testing.T) {
 	}
 }
 
-// TestVersionOptionalFields performs tests to ensure that an encoded version
-// messages that omit optional fields are handled correctly.
-func TestVersionOptionalFields(t *testing.T) {
-	// onlyRequiredVersion is a version message that only contains the
-	// required versions and all other values set to their default values.
-	onlyRequiredVersion := MsgVersion{
-		ProtocolVersion: 60002,
-		Services:        SFNodeNetwork,
-		Timestamp:       time.Unix(0x495fab29, 0), // 2009-01-03 12:15:05 -0600 CST)
-		AddrYou: NetAddress{
-			Timestamp: time.Time{}, // Zero value -- no timestamp in version
-			Services:  SFNodeNetwork,
-			IP:        net.ParseIP("192.168.0.1"),
-			Port:      8333,
-		},
-	}
-	onlyRequiredVersionEncoded := make([]byte, len(baseVersionEncoded)-55)
-	copy(onlyRequiredVersionEncoded, baseVersionEncoded)
-
-	// addrMeVersion is a version message that contains all fields through
-	// the AddrMe field.
-	addrMeVersion := onlyRequiredVersion
-	addrMeVersion.AddrMe = NetAddress{
-		Timestamp: time.Time{}, // Zero value -- no timestamp in version
-		Services:  SFNodeNetwork,
-		IP:        net.ParseIP("127.0.0.1"),
-		Port:      8333,
-	}
-	addrMeVersionEncoded := make([]byte, len(baseVersionEncoded)-29)
-	copy(addrMeVersionEncoded, baseVersionEncoded)
-
-	// nonceVersion is a version message that contains all fields through
-	// the Nonce field.
-	nonceVersion := addrMeVersion
-	nonceVersion.Nonce = 123123 // 0x1e0f3
-	nonceVersionEncoded := make([]byte, len(baseVersionEncoded)-21)
-	copy(nonceVersionEncoded, baseVersionEncoded)
-
-	// uaVersion is a version message that contains all fields through
-	// the UserAgent field.
-	uaVersion := nonceVersion
-	uaVersion.UserAgent = "/btcdtest:0.0.1/"
-	uaVersionEncoded := make([]byte, len(baseVersionEncoded)-4)
-	copy(uaVersionEncoded, baseVersionEncoded)
-
-	// lastBlockVersion is a version message that contains all fields
-	// through the LastBlock field.
-	lastBlockVersion := uaVersion
-	lastBlockVersion.LastBlock = 234234 // 0x392fa
-	lastBlockVersionEncoded := make([]byte, len(baseVersionEncoded))
-	copy(lastBlockVersionEncoded, baseVersionEncoded)
-
-	tests := []struct {
-		msg  *MsgVersion // Expected message
-		buf  []byte      // Wire encoding
-		pver uint32      // Protocol version for wire encoding
-	}{
-		{
-			&onlyRequiredVersion,
-			onlyRequiredVersionEncoded,
-			ProtocolVersion,
-		},
-		{
-			&addrMeVersion,
-			addrMeVersionEncoded,
-			ProtocolVersion,
-		},
-		{
-			&nonceVersion,
-			nonceVersionEncoded,
-			ProtocolVersion,
-		},
-		{
-			&uaVersion,
-			uaVersionEncoded,
-			ProtocolVersion,
-		},
-		{
-			&lastBlockVersion,
-			lastBlockVersionEncoded,
-			ProtocolVersion,
-		},
-	}
-
-	for i, test := range tests {
-		// Decode the message from wire format.
-		var msg MsgVersion
-		rbuf := bytes.NewBuffer(test.buf)
-		err := msg.BtcDecode(rbuf, test.pver)
-		if err != nil {
-			t.Errorf("BtcDecode #%d error %v", i, err)
-			continue
-		}
-		if !reflect.DeepEqual(&msg, test.msg) {
-			t.Errorf("BtcDecode #%d\n got: %s want: %s", i,
-				spew.Sdump(msg), spew.Sdump(test.msg))
-			continue
-		}
-	}
-}
-
 // baseVersion is used in the various tests as a baseline MsgVersion.
 var baseVersion = &MsgVersion{
 	ProtocolVersion: 60002,
@@ -417,9 +322,9 @@ var baseVersion = &MsgVersion{
 		IP:        net.ParseIP("127.0.0.1"),
 		Port:      8333,
 	},
-	Nonce:     123123, // 0x1e0f3
-	UserAgent: "/btcdtest:0.0.1/",
-	LastBlock: 234234, // 0x392fa
+	Nonce:       123123, // 0x1e0f3
+	UserAgent:   "/btcdtest:0.0.1/",
+	SelectedTip: &daghash.Hash{0x12, 0x34},
 }
 
 // baseVersionEncoded is the wire encoded bytes for baseVersion using protocol
@@ -445,12 +350,14 @@ var baseVersionEncoded = []byte{
 	0x10, // Varint for user agent length
 	0x2f, 0x62, 0x74, 0x63, 0x64, 0x74, 0x65, 0x73,
 	0x74, 0x3a, 0x30, 0x2e, 0x30, 0x2e, 0x31, 0x2f, // User agent
-	0xfa, 0x92, 0x03, 0x00, // Last block
+	0x12, 0x34, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // Selected Tip
 }
 
-// baseVersionBIP0037 is used in the various tests as a baseline MsgVersion for
-// BIP0037.
-var baseVersionBIP0037 = &MsgVersion{
+// baseVersionWithRelayTx is used in the various tests as a baseline MsgVersion
+var baseVersionWithRelayTx = &MsgVersion{
 	ProtocolVersion: 70001,
 	Services:        SFNodeNetwork,
 	Timestamp:       time.Unix(0x495fab29, 0), // 2009-01-03 12:15:05 -0600 CST)
@@ -466,14 +373,14 @@ var baseVersionBIP0037 = &MsgVersion{
 		IP:        net.ParseIP("127.0.0.1"),
 		Port:      8333,
 	},
-	Nonce:     123123, // 0x1e0f3
-	UserAgent: "/btcdtest:0.0.1/",
-	LastBlock: 234234, // 0x392fa
+	Nonce:       123123, // 0x1e0f3
+	UserAgent:   "/btcdtest:0.0.1/",
+	SelectedTip: &daghash.Hash{0x12, 0x34},
 }
 
-// baseVersionBIP0037Encoded is the wire encoded bytes for baseVersionBIP0037
-// using protocol version BIP0037Version and is used in the various tests.
-var baseVersionBIP0037Encoded = []byte{
+// baseVersionWithRelayTxEncoded is the wire encoded bytes for
+// baseVersionWithRelayTx and is used in the various tests.
+var baseVersionWithRelayTxEncoded = []byte{
 	0x71, 0x11, 0x01, 0x00, // Protocol version 70001
 	0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // SFNodeNetwork
 	0x29, 0xab, 0x5f, 0x49, 0x00, 0x00, 0x00, 0x00, // 64-bit Timestamp
@@ -490,10 +397,13 @@ var baseVersionBIP0037Encoded = []byte{
 	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x00, 0xff, 0xff, 0x7f, 0x00, 0x00, 0x01, // IP 127.0.0.1
 	0x20, 0x8d, // Port 8333 in big-endian
-	0xf3, 0xe0, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, // Fake Nonce. TODO: (Ori) Replace to a real nonce
+	0xf3, 0xe0, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, // Nonce
 	0x10, // Varint for user agent length
 	0x2f, 0x62, 0x74, 0x63, 0x64, 0x74, 0x65, 0x73,
 	0x74, 0x3a, 0x30, 0x2e, 0x30, 0x2e, 0x31, 0x2f, // User agent
-	0xfa, 0x92, 0x03, 0x00, // Last block
+	0x12, 0x34, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // Selected Tip
 	0x01, // Relay tx
 }