Fixes issue #15. All tests successful with Python3.9. Review required though

docs/root/source/installation/node-setup/configuration.md

@@ -300,7 +300,7 @@ full path to the file where error logs should be written.
 ### log.level_console
 
 The log level used to log to the console. Possible allowed values are the ones
-defined by [Python](https://docs.python.org/3.6/library/logging.html#levels),
+defined by [Python](https://docs.python.org/3.9/library/logging.html#levels),
 but case-insensitive for the sake of convenience:
 
 ```text
@@ -310,7 +310,7 @@ but case-insensitive for the sake of convenience:
 ### log.level_logfile
 
 The log level used to log to the log file. Possible allowed values are the ones
-defined by [Python](https://docs.python.org/3.6/library/logging.html#levels),
+defined by [Python](https://docs.python.org/3.9/library/logging.html#levels),
 but case-insensitive for the sake of convenience:
 
 ```text
@@ -323,7 +323,7 @@ The format string for the date/time portion of a message, when logged to the
 console.
 
 For more information on how to construct the format string please consult the
-table under [Python's documentation of time.strftime(format[, t])](https://docs.python.org/3.6/library/time.html#time.strftime).
+table under [Python's documentation of time.strftime(format[, t])](https://docs.python.org/3.9/library/time.html#time.strftime).
 
 ### log.datefmt_logfile
 
@@ -331,7 +331,7 @@ The format string for the date/time portion of a message, when logged to a log
  file.
 
 For more information on how to construct the format string please consult the
-table under [Python's documentation of time.strftime(format[, t])](https://docs.python.org/3.6/library/time.html#time.strftime).
+table under [Python's documentation of time.strftime(format[, t])](https://docs.python.org/3.9/library/time.html#time.strftime).
 
 ### log.fmt_console
 
@@ -339,7 +339,7 @@ A string used to format the log messages when logged to the console.
 
 For more information on possible formatting options please consult Python's
 documentation on
-[LogRecord attributes](https://docs.python.org/3.6/library/logging.html#logrecord-attributes).
+[LogRecord attributes](https://docs.python.org/3.9/library/logging.html#logrecord-attributes).
 
 ### log.fmt_logfile
 
@@ -347,7 +347,7 @@ A string used to format the log messages when logged to a log file.
 
 For more information on possible formatting options please consult Python's
 documentation on
-[LogRecord attributes](https://docs.python.org/3.6/library/logging.html#logrecord-attributes).
+[LogRecord attributes](https://docs.python.org/3.9/library/logging.html#logrecord-attributes).
 
 ### log.granular_levels
 

docs/root/source/installation/node-setup/planetmint-cli.md

@@ -74,7 +74,7 @@ $ planetmint --log-level INFO start
 
 The allowed levels are `DEBUG`, `INFO`, `WARNING`, `ERROR`, and `CRITICAL`.
 For an explanation regarding these levels please consult the
-[Logging Levels](https://docs.python.org/3.6/library/logging.html#levels)
+[Logging Levels](https://docs.python.org/3.9/library/logging.html#levels)
 section of Python's documentation.
 
 For a more fine-grained control over the logging configuration you can use the

docs/root/source/installation/node-setup/production-node/node-requirements.md

@@ -13,7 +13,7 @@ Code is Apache-2.0 and docs are CC-BY-4.0
 
 Planetmint Server requires Python 3.5+ and Python 3.5+ [will run on any modern OS](https://docs.python.org/3.5/using/index.html), but we recommend using an LTS version of [Ubuntu Server](https://www.ubuntu.com/server) or a similarly server-grade Linux distribution.
 
-_Don't use macOS_ (formerly OS X, formerly Mac OS X), because it's not a server-grade operating system. Also, BigchaindB Server uses the Python multiprocessing package and [some functionality in the multiprocessing package doesn't work on Mac OS X](https://docs.python.org/3.6/library/multiprocessing.html#multiprocessing.Queue.qsize).
+_Don't use macOS_ (formerly OS X, formerly Mac OS X), because it's not a server-grade operating system. Also, Planetmint Server uses the Python multiprocessing package and [some functionality in the multiprocessing package doesn't work on Mac OS X](https://docs.python.org/3.9/library/multiprocessing.html#multiprocessing.Queue.qsize).
 
 ## General Considerations
 

docs/root/source/installation/node-setup/set-up-node-software.md

@@ -13,7 +13,7 @@ MongoDB and Tendermint.
 
 ## Install Planetmint Server
 
-Planetmint Server requires **Python 3.6+**, so make sure your system has it.
+Planetmint Server requires **Python 3.9+**, so make sure your system has it.
 
 Install the required OS-level packages: