diff --git a/tests/e2e/ctl_v3_snapshot_test.go b/tests/e2e/ctl_v3_snapshot_test.go
index 22db112da..9047f64ac 100644
--- a/tests/e2e/ctl_v3_snapshot_test.go
+++ b/tests/e2e/ctl_v3_snapshot_test.go
@@ -171,8 +171,6 @@ func testIssue6361(t *testing.T) {
 	}
 
 	e2e.BeforeTest(t)
-	os.Setenv("ETCDCTL_API", "3")
-	defer os.Unsetenv("ETCDCTL_API")
 
 	epc, err := e2e.NewEtcdProcessCluster(context.TODO(), t, &e2e.EtcdProcessClusterConfig{
 		ClusterSize:  1,
diff --git a/tests/e2e/etcd_release_upgrade_test.go b/tests/e2e/etcd_release_upgrade_test.go
index c72585929..88f97ca73 100644
--- a/tests/e2e/etcd_release_upgrade_test.go
+++ b/tests/e2e/etcd_release_upgrade_test.go
@@ -17,7 +17,6 @@ package e2e
 import (
 	"context"
 	"fmt"
-	"os"
 	"sync"
 	"testing"
 	"time"
@@ -52,8 +51,6 @@ func TestReleaseUpgrade(t *testing.T) {
 		}
 	}()
 
-	os.Setenv("ETCDCTL_API", "3")
-	defer os.Unsetenv("ETCDCTL_API")
 	cx := ctlCtx{
 		t:           t,
 		cfg:         *e2e.NewConfigNoTLS(),
@@ -138,8 +135,6 @@ func TestReleaseUpgradeWithRestart(t *testing.T) {
 		}
 	}()
 
-	os.Setenv("ETCDCTL_API", "3")
-	defer os.Unsetenv("ETCDCTL_API")
 	cx := ctlCtx{
 		t:           t,
 		cfg:         *e2e.NewConfigNoTLS(),
diff --git a/tests/e2e/gateway_test.go b/tests/e2e/gateway_test.go
index 6a7b03bd2..ebd179e74 100644
--- a/tests/e2e/gateway_test.go
+++ b/tests/e2e/gateway_test.go
@@ -16,7 +16,6 @@ package e2e
 
 import (
 	"context"
-	"os"
 	"strings"
 	"testing"
 
@@ -40,9 +39,6 @@ func TestGateway(t *testing.T) {
 	p := startGateway(t, eps)
 	defer p.Stop()
 
-	os.Setenv("ETCDCTL_API", "3")
-	defer os.Unsetenv("ETCDCTL_API")
-
 	err = e2e.SpawnWithExpect([]string{e2e.CtlBinPath, "--endpoints=" + defaultGatewayEndpoint, "put", "foo", "bar"}, "OK\r\n")
 	if err != nil {
 		t.Errorf("failed to finish put request through gateway: %v", err)
diff --git a/tests/framework/e2e/etcd_spawn_cov.go b/tests/framework/e2e/etcd_spawn_cov.go
index 84d680385..f8cdd194f 100644
--- a/tests/framework/e2e/etcd_spawn_cov.go
+++ b/tests/framework/e2e/etcd_spawn_cov.go
@@ -45,9 +45,6 @@ func SpawnCmdWithLogger(lg *zap.Logger, args []string, envVars map[string]string
 		cmd = cmd + "_test"
 	case strings.HasSuffix(cmd, "/etcdutl"):
 		cmd = cmd + "_test"
-	case strings.HasSuffix(cmd, "/etcdctl3"):
-		cmd = CtlBinPath + "_test"
-		env = append(env, "ETCDCTL_API=3")
 	}
 
 	wd, err := os.Getwd()
diff --git a/tests/framework/e2e/etcd_spawn_nocov.go b/tests/framework/e2e/etcd_spawn_nocov.go
index d050e8b52..46748ede1 100644
--- a/tests/framework/e2e/etcd_spawn_nocov.go
+++ b/tests/framework/e2e/etcd_spawn_nocov.go
@@ -18,10 +18,8 @@
 package e2e
 
 import (
-	"os"
-	"strings"
-
 	"go.uber.org/zap"
+	"os"
 
 	"go.etcd.io/etcd/pkg/v3/expect"
 )
@@ -34,15 +32,6 @@ func SpawnCmdWithLogger(lg *zap.Logger, args []string, envVars map[string]string
 		return nil, err
 	}
 	env := mergeEnvVariables(envVars)
-	if strings.HasSuffix(args[0], "/etcdctl3") {
-		env = append(env, "ETCDCTL_API=3")
-		lg.Info("spawning process with ETCDCTL_API=3",
-			zap.Strings("args", args),
-			zap.String("working-dir", wd),
-			zap.String("name", name),
-			zap.Strings("environment-variables", env))
-		return expect.NewExpectWithEnv(CtlBinPath, args[1:], env, name)
-	}
 	lg.Info("spawning process",
 		zap.Strings("args", args),
 		zap.String("working-dir", wd),
diff --git a/tests/framework/e2e/etcdctl.go b/tests/framework/e2e/etcdctl.go
index 1c114e524..024bd9d74 100644
--- a/tests/framework/e2e/etcdctl.go
+++ b/tests/framework/e2e/etcdctl.go
@@ -268,7 +268,7 @@ func (ctl *EtcdctlV3) MemberRemove(ctx context.Context, id uint64) (*clientv3.Me
 }
 
 func (ctl *EtcdctlV3) cmdArgs(args ...string) []string {
-	cmdArgs := []string{CtlBinPath + "3"}
+	cmdArgs := []string{CtlBinPath}
 	for k, v := range ctl.flags() {
 		cmdArgs = append(cmdArgs, fmt.Sprintf("--%s=%s", k, v))
 	}
diff --git a/tests/framework/e2e/flags.go b/tests/framework/e2e/flags.go
index 9a2c933d2..ce6d6dea6 100644
--- a/tests/framework/e2e/flags.go
+++ b/tests/framework/e2e/flags.go
@@ -45,7 +45,6 @@ var (
 
 func InitFlags() {
 	os.Setenv("ETCD_UNSUPPORTED_ARCH", runtime.GOARCH)
-	os.Unsetenv("ETCDCTL_API")
 
 	binDirDef := integration.MustAbsPath("../../bin")
 	certDirDef := FixturesDir
diff --git a/tests/functional/README.md b/tests/functional/README.md
index 50f82c95f..933abe142 100644
--- a/tests/functional/README.md
+++ b/tests/functional/README.md
@@ -47,8 +47,8 @@ $ make build-functional
 $ ./bin/etcd-proxy --help
 $ ./bin/etcd-proxy --from localhost:23790 --to localhost:2379 --http-port 2378 --verbose
 
-$ ETCDCTL_API=3 ./bin/etcdctl --endpoints localhost:2379 put foo bar
-$ ETCDCTL_API=3 ./bin/etcdctl --endpoints localhost:23790 put foo bar
+$ ./bin/etcdctl --endpoints localhost:2379 put foo bar
+$ ./bin/etcdctl --endpoints localhost:23790 put foo bar
 ```
 
 Proxy overhead per request is under 500μs
@@ -151,7 +151,7 @@ $ curl -L http://localhost:2378/delay-tx -X PUT \
 $ curl -L http://localhost:2378/delay-tx
 # current send latency 4.92143955s
 
-$ ETCDCTL_API=3 ./bin/etcdctl \
+$ ./bin/etcdctl \
   --endpoints localhost:23790 \
   --command-timeout=3s \
   put foo bar
@@ -163,7 +163,7 @@ $ curl -L http://localhost:2378/delay-tx -X DELETE
 $ curl -L http://localhost:2378/delay-tx
 # current send latency 0s
 
-$ ETCDCTL_API=3 ./bin/etcdctl \
+$ ./bin/etcdctl \
   --endpoints localhost:23790 \
   --command-timeout=3s \
   put foo bar
@@ -176,7 +176,7 @@ Pause client transmit
 $ curl -L http://localhost:2378/pause-tx -X PUT
 # paused forwarding [tcp://localhost:23790 -> tcp://localhost:2379]
 
-$ ETCDCTL_API=3 ./bin/etcdctl \
+$ ./bin/etcdctl \
   --endpoints localhost:23790 \
   put foo bar
 # Error: context deadline exceeded
@@ -191,7 +191,7 @@ Drop client packets
 $ curl -L http://localhost:2378/blackhole-tx -X PUT
 # blackholed; dropping packets [tcp://localhost:23790 -> tcp://localhost:2379]
 
-$ ETCDCTL_API=3 ./bin/etcdctl --endpoints localhost:23790 put foo bar
+$ ./bin/etcdctl --endpoints localhost:23790 put foo bar
 # Error: context deadline exceeded
 
 $ curl -L http://localhost:2378/blackhole-tx -X DELETE
@@ -207,7 +207,7 @@ $ make build-functional
 $ rm -rf /tmp/etcd-proxy-data.s*
 $ goreman -f ./functional/Procfile-proxy start
 
-$ ETCDCTL_API=3 ./bin/etcdctl \
+$ ./bin/etcdctl \
   --endpoints localhost:13790,localhost:23790,localhost:33790 \
   member list
 
diff --git a/tests/manual/docker-dns-srv/certs-gateway/run.sh b/tests/manual/docker-dns-srv/certs-gateway/run.sh
index ef4c1667c..d70cb1e76 100755
--- a/tests/manual/docker-dns-srv/certs-gateway/run.sh
+++ b/tests/manual/docker-dns-srv/certs-gateway/run.sh
@@ -11,35 +11,35 @@ goreman -f /certs-gateway/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-gateway/ca.crt \
   --cert=/certs-gateway/server.crt \
   --key=/certs-gateway/server.key.insecure \
   --discovery-srv etcd.local \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-gateway/ca.crt \
   --cert=/certs-gateway/server.crt \
   --key=/certs-gateway/server.key.insecure \
   --discovery-srv etcd.local \
   put abc def
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-gateway/ca.crt \
   --cert=/certs-gateway/server.crt \
   --key=/certs-gateway/server.key.insecure \
   --discovery-srv etcd.local \
   get abc
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-gateway/ca.crt \
   --cert=/certs-gateway/server.crt \
   --key=/certs-gateway/server.key.insecure \
   --endpoints=127.0.0.1:23790 \
   put ghi jkl
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-gateway/ca.crt \
   --cert=/certs-gateway/server.crt \
   --key=/certs-gateway/server.key.insecure \
diff --git a/tests/manual/docker-dns-srv/certs-wildcard/run.sh b/tests/manual/docker-dns-srv/certs-wildcard/run.sh
index 13e16bda9..cc4000ef0 100755
--- a/tests/manual/docker-dns-srv/certs-wildcard/run.sh
+++ b/tests/manual/docker-dns-srv/certs-wildcard/run.sh
@@ -11,21 +11,21 @@ goreman -f /certs-wildcard/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-wildcard/ca.crt \
   --cert=/certs-wildcard/server.crt \
   --key=/certs-wildcard/server.key.insecure \
   --discovery-srv etcd.local \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-wildcard/ca.crt \
   --cert=/certs-wildcard/server.crt \
   --key=/certs-wildcard/server.key.insecure \
   --discovery-srv etcd.local \
   put abc def
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-wildcard/ca.crt \
   --cert=/certs-wildcard/server.crt \
   --key=/certs-wildcard/server.key.insecure \
diff --git a/tests/manual/docker-dns-srv/certs/run.sh b/tests/manual/docker-dns-srv/certs/run.sh
index 44d5920b6..d70f355ba 100755
--- a/tests/manual/docker-dns-srv/certs/run.sh
+++ b/tests/manual/docker-dns-srv/certs/run.sh
@@ -11,28 +11,28 @@ goreman -f /certs/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \
   --discovery-srv etcd.local \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \
   --discovery-srv etcd.local \
   put abc def
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \
   --discovery-srv etcd.local \
   get abc
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \
@@ -40,7 +40,7 @@ ETCDCTL_API=3 ./etcdctl \
   --discovery-srv-name c1 \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \
@@ -48,7 +48,7 @@ ETCDCTL_API=3 ./etcdctl \
   --discovery-srv-name c1 \
   put ghi jkl
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \
diff --git a/tests/manual/docker-dns/certs-common-name-auth/run.sh b/tests/manual/docker-dns/certs-common-name-auth/run.sh
index d4aaaecf2..f46d642ae 100755
--- a/tests/manual/docker-dns/certs-common-name-auth/run.sh
+++ b/tests/manual/docker-dns/certs-common-name-auth/run.sh
@@ -11,21 +11,21 @@ goreman -f /certs-common-name-auth/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
   --endpoints=https://m1.etcd.local:2379 \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
   --endpoints=https://m1.etcd.local:2379,https://m2.etcd.local:22379,https://m3.etcd.local:32379 \
   put abc def
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -34,7 +34,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 1. creating root role"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -43,7 +43,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 2. granting readwrite 'foo' permission to role 'root'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -52,7 +52,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 3. getting role 'root'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -61,7 +61,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 4. creating user 'root'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -71,7 +71,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 5. granting role 'root' to user 'root'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -80,7 +80,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 6. getting user 'root'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -89,7 +89,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 7. enabling auth"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -98,7 +98,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 8. writing 'foo' with 'root:123'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -108,7 +108,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 9. writing 'aaa' with 'root:123'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -118,7 +118,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 10. writing 'foo' without 'root:123'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -127,7 +127,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 11. reading 'foo' with 'root:123'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -137,7 +137,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 12. reading 'aaa' with 'root:123'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -147,7 +147,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 13. creating a new user 'test-common-name:test-pass'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -158,7 +158,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 14. creating a role 'test-role'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -168,7 +168,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 15. granting readwrite 'aaa' --prefix permission to role 'test-role'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -178,7 +178,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 16. getting role 'test-role'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -188,7 +188,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 17. granting role 'test-role' to user 'test-common-name'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -198,7 +198,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 18. writing 'aaa' with 'test-common-name:test-pass'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -208,7 +208,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 19. writing 'bbb' with 'test-common-name:test-pass'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -218,7 +218,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 20. reading 'aaa' with 'test-common-name:test-pass'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -228,7 +228,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 21. reading 'bbb' with 'test-common-name:test-pass'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -238,7 +238,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 22. writing 'aaa' with CommonName 'test-common-name'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
@@ -247,7 +247,7 @@ ETCDCTL_API=3 ./etcdctl \
 
 sleep 1s && printf "\n"
 echo "Step 23. reading 'aaa' with CommonName 'test-common-name'"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-auth/ca.crt \
   --cert=/certs-common-name-auth/server.crt \
   --key=/certs-common-name-auth/server.key.insecure \
diff --git a/tests/manual/docker-dns/certs-common-name-multi/run.sh b/tests/manual/docker-dns/certs-common-name-multi/run.sh
index 2ccb6b678..92c4ca0d8 100755
--- a/tests/manual/docker-dns/certs-common-name-multi/run.sh
+++ b/tests/manual/docker-dns/certs-common-name-multi/run.sh
@@ -11,21 +11,21 @@ goreman -f /certs-common-name-multi/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-multi/ca.crt \
   --cert=/certs-common-name-multi/server-1.crt \
   --key=/certs-common-name-multi/server-1.key.insecure \
   --endpoints=https://m1.etcd.local:2379 \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-multi/ca.crt \
   --cert=/certs-common-name-multi/server-2.crt \
   --key=/certs-common-name-multi/server-2.key.insecure \
   --endpoints=https://m1.etcd.local:2379,https://m2.etcd.local:22379,https://m3.etcd.local:32379 \
   put abc def
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-common-name-multi/ca.crt \
   --cert=/certs-common-name-multi/server-3.crt \
   --key=/certs-common-name-multi/server-3.key.insecure \
diff --git a/tests/manual/docker-dns/certs-gateway/run.sh b/tests/manual/docker-dns/certs-gateway/run.sh
index 94fdc32ee..3110f3b46 100755
--- a/tests/manual/docker-dns/certs-gateway/run.sh
+++ b/tests/manual/docker-dns/certs-gateway/run.sh
@@ -11,35 +11,35 @@ goreman -f /certs-gateway/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-gateway/ca.crt \
   --cert=/certs-gateway/server.crt \
   --key=/certs-gateway/server.key.insecure \
   --endpoints=https://m1.etcd.local:2379 \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-gateway/ca.crt \
   --cert=/certs-gateway/server.crt \
   --key=/certs-gateway/server.key.insecure \
   --endpoints=https://m1.etcd.local:2379,https://m2.etcd.local:22379,https://m3.etcd.local:32379 \
   put abc def
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-gateway/ca.crt \
   --cert=/certs-gateway/server.crt \
   --key=/certs-gateway/server.key.insecure \
   --endpoints=https://m1.etcd.local:2379,https://m2.etcd.local:22379,https://m3.etcd.local:32379 \
   get abc
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-gateway/ca.crt \
   --cert=/certs-gateway/server.crt \
   --key=/certs-gateway/server.key.insecure \
   --endpoints=127.0.0.1:23790 \
   put ghi jkl
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-gateway/ca.crt \
   --cert=/certs-gateway/server.crt \
   --key=/certs-gateway/server.key.insecure \
diff --git a/tests/manual/docker-dns/certs-san-dns/run.sh b/tests/manual/docker-dns/certs-san-dns/run.sh
index 5d0a3d47d..f4227c58e 100755
--- a/tests/manual/docker-dns/certs-san-dns/run.sh
+++ b/tests/manual/docker-dns/certs-san-dns/run.sh
@@ -13,7 +13,7 @@ goreman -f /certs-san-dns/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
  --cacert=/certs-san-dns/ca.crt \
  --cert=/certs-san-dns/server-1.crt \
  --key=/certs-san-dns/server-1.key.insecure \
@@ -21,7 +21,7 @@ ETCDCTL_API=3 ./etcdctl \
  endpoint health --cluster
 
 printf "\nPut abc \n"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
  --cacert=/certs-san-dns/ca.crt \
  --cert=/certs-san-dns/server-2.crt \
  --key=/certs-san-dns/server-2.key.insecure \
@@ -29,7 +29,7 @@ ETCDCTL_API=3 ./etcdctl \
  put abc def
 
 printf "\nGet abc \n"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
  --cacert=/certs-san-dns/ca.crt \
  --cert=/certs-san-dns/server-3.crt \
  --key=/certs-san-dns/server-3.key.insecure \
@@ -41,7 +41,7 @@ kill $(lsof -t -i:2379)
 sleep 7s
 
 printf "\nGet abc after killing server 1\n"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
  --cacert=/certs-san-dns/ca.crt \
  --cert=/certs-san-dns/server-2.crt \
  --key=/certs-san-dns/server-2.key.insecure \
diff --git a/tests/manual/docker-dns/certs-wildcard/run.sh b/tests/manual/docker-dns/certs-wildcard/run.sh
index 683a4d28a..f0374d909 100755
--- a/tests/manual/docker-dns/certs-wildcard/run.sh
+++ b/tests/manual/docker-dns/certs-wildcard/run.sh
@@ -11,21 +11,21 @@ goreman -f /certs-wildcard/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-wildcard/ca.crt \
   --cert=/certs-wildcard/server.crt \
   --key=/certs-wildcard/server.key.insecure \
   --endpoints=https://m1.etcd.local:2379 \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-wildcard/ca.crt \
   --cert=/certs-wildcard/server.crt \
   --key=/certs-wildcard/server.key.insecure \
   --endpoints=https://m1.etcd.local:2379,https://m2.etcd.local:22379,https://m3.etcd.local:32379 \
   put abc def
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-wildcard/ca.crt \
   --cert=/certs-wildcard/server.crt \
   --key=/certs-wildcard/server.key.insecure \
diff --git a/tests/manual/docker-dns/certs/run.sh b/tests/manual/docker-dns/certs/run.sh
index 8faec3458..05be3e642 100755
--- a/tests/manual/docker-dns/certs/run.sh
+++ b/tests/manual/docker-dns/certs/run.sh
@@ -11,21 +11,21 @@ goreman -f /certs/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \
   --endpoints=https://m1.etcd.local:2379 \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \
   --endpoints=https://m1.etcd.local:2379,https://m2.etcd.local:22379,https://m3.etcd.local:32379 \
   put abc def
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \
diff --git a/tests/manual/docker-dns/insecure/run.sh b/tests/manual/docker-dns/insecure/run.sh
index 6b2476228..32c963487 100755
--- a/tests/manual/docker-dns/insecure/run.sh
+++ b/tests/manual/docker-dns/insecure/run.sh
@@ -11,15 +11,15 @@ goreman -f /insecure/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --endpoints=http://m1.etcd.local:2379 \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --endpoints=http://m1.etcd.local:2379,http://m2.etcd.local:22379,http://m3.etcd.local:32379 \
   put abc def
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --endpoints=http://m1.etcd.local:2379,http://m2.etcd.local:22379,http://m3.etcd.local:32379 \
   get abc
 
diff --git a/tests/manual/docker-static-ip/certs-metrics-proxy/run.sh b/tests/manual/docker-static-ip/certs-metrics-proxy/run.sh
index 6089f3ed9..9b171f190 100755
--- a/tests/manual/docker-static-ip/certs-metrics-proxy/run.sh
+++ b/tests/manual/docker-static-ip/certs-metrics-proxy/run.sh
@@ -6,21 +6,21 @@ goreman -f /certs-metrics-proxy/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-metrics-proxy/ca.crt \
   --cert=/certs-metrics-proxy/server.crt \
   --key=/certs-metrics-proxy/server.key.insecure \
   --endpoints=https://localhost:2379 \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-metrics-proxy/ca.crt \
   --cert=/certs-metrics-proxy/server.crt \
   --key=/certs-metrics-proxy/server.key.insecure \
   --endpoints=https://localhost:2379,https://localhost:22379,https://localhost:32379 \
   put abc def
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs-metrics-proxy/ca.crt \
   --cert=/certs-metrics-proxy/server.crt \
   --key=/certs-metrics-proxy/server.key.insecure \
@@ -86,14 +86,14 @@ curl -L http://localhost:39379/metrics | grep Put | tail -3
 
 #################
 sleep 3s && printf "\n\n" && echo "Requests to gRPC proxy localhost:23790"
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert /certs-metrics-proxy/ca.crt \
   --cert /certs-metrics-proxy/server.crt \
   --key /certs-metrics-proxy/server.key.insecure \
   --endpoints=localhost:23790 \
   put ghi jkl
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert /certs-metrics-proxy/ca.crt \
   --cert /certs-metrics-proxy/server.crt \
   --key /certs-metrics-proxy/server.key.insecure \
diff --git a/tests/manual/docker-static-ip/certs/run.sh b/tests/manual/docker-static-ip/certs/run.sh
index 6d25038de..4e63a7caf 100755
--- a/tests/manual/docker-static-ip/certs/run.sh
+++ b/tests/manual/docker-static-ip/certs/run.sh
@@ -6,21 +6,21 @@ goreman -f /certs/Procfile start &
 # TODO: remove random sleeps
 sleep 7s
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \
   --endpoints=https://localhost:2379 \
   endpoint health --cluster
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \
   --endpoints=https://localhost:2379,https://localhost:22379,https://localhost:32379 \
   put abc def
 
-ETCDCTL_API=3 ./etcdctl \
+./etcdctl \
   --cacert=/certs/ca.crt \
   --cert=/certs/server.crt \
   --key=/certs/server.key.insecure \