Is there Upgrade guidance / documentation available?

I found the Admin Guide, but the install and configuration sections seem to be tailored to a new install. What’s available to help plan and execute an upgrade to the latest version of server and clients? I’m currently stuck at 3.1 on the server and 6.4 on the clients.

Not looking for hand-holding or n00b stuff, just a general overview of what’s involved in an upgrade and the likely things to break if I don’t do it right.

Some specific things I can think of:

  • Can I go directly from 3.1/6.4 to 3.3/8.1 or do I need to get 3.2/8.0 working first?
  • My database is stored on a SQL server 2014, any potential problems with that vs. the “redistributable SQL”?
  • Am I right in understanding that previous version clients not supported means they keep working as-is until I get them upgraded, I just can’t make any changes to them from the console anymore?

Edit: Link provided to me by Comodo support. Comodo Help