redis works with python 2.7 too.

Remove requirement that python 3.6 be used. Earlier version of redis-py
can meet roundup's requirement.

Author: rouilj

doc/admin_guide.txt

@@ -492,10 +492,9 @@ Using Redis for Session Databases
 
 Redis is an in memory key/value data structure store.
 
-To use redis you must be using Python 3.6 or newer.  You
-need to install the redis-py_ module from pypi. Then install
-Redis using your package manager or by downloading it from
-the Redis_ website.
+You need to install the redis-py_ module from pypi. Then
+install Redis using your package manager or by downloading
+it from the Redis_ website.
 
 You need to secure your redis instance. The data that
 Roundup stores includes session cookies and other

doc/upgrading.txt

@@ -115,11 +115,10 @@ SQLite databases. If you want to keep using the data set the
 Session/OTK data storage using Redis (optional)
 -----------------------------------------------
 
-If you are running Roundup with Python 3.6 or newer, you can
-store your ephemeral data in a Redis database. This provides
-significantly better performance for ephemeral data than 
-SQLite or dbm files. See the section `Using Redis for Session
-Databases`_ in the `administration guide`_
+You can store your ephemeral data in a Redis database. This
+provides significantly better performance for ephemeral data
+than SQLite or dbm files. See the section `Using Redis for
+Session Databases`_ in the `administration guide`_
 
 
 .. _Using Redis for Session Databases: