I am in the throes of making the upgrade captioned above. If there was a documented procedure or a list of potential issues to help I would be grateful. Maybe I should upgrade CiviCRM to a leter version first??
The first issue to raise is that CiviCRM 4.4 is not necessarily compatible with Joomla 3.5 according to this post: https://civicrm.org/blog/colemanw/announcing-civicrm-445 Since CiviCRM 4.6 apparently is compatible with Joomla 2.5, I suggest upgrading Civi first from 4.4 to 4.6. Most CiviCRM documentation has to do with upgrading CiviCRM, rather than upgrading Joomla, so I'm not prepared to give advice on Joomla upgrades specifically.
The point that Stuart (CiviTeacher) made is a good general principle: separate your CiviCRM upgrade from your CMS upgrade. Reduce the number of moving parts.
Specifically regarding Joomla 2.5 to 3.5, there's not too much to worry about from the CiviCRM perspective so long as you're running a CiviCRM version that's compatible with both Joomla versions (like 4.6.x, as Stuart suggested). My coworkers and I have run a number of these without incident.
In practice, you'll probably want to copy your Joomla site, upgrade the copy and upgrade or replace it's extensions, and then make that copy be the new production site. This works great for a CMS, where you can tell everyone, "Hold your edits: I'm upgrading the site." However, with CiviCRM, someone might make a donation out of the blue during the time you're upgrading the site copy.
Plan on copying the CiviCRM tables from the J2.5 site to the J3.5 site just before launch. If CiviCRM is the same version, and you're using the same URL, you'll just need to check the file paths (in the two
civicrm.settings.php files, and then by visiting Administer - System Settings - Clear Caches and Update Paths) and then clear the contents of
But again, the big thing is to keep the CiviCRM part of it as simple as possible by doing a regular CiviCRM upgrade, a Joomla upgrade, and then (if necessary) a regular CiviCRM upgrade to your final intended version. Don't mix CiviCRM changes into the Joomla upgrade work.