I'm using version 1.2.13, is it okay to upgrade that one directly to the latest version of MyBB?
Don't use the package in that above link, that's the changed files pack for users on 1.4.3, not the full package
Lufbra, you'll have to download the complete 1.4.4 package. Then do the usual, close board, deactivate all plugins, make sure you have a full database backup, and backup your files. Then save your copy of ./inc/config.php and ./inc/settings.php and delete all your 1.2.13 files. Upload the 1.4.4 ones, delete the ./inc/config.default.php that you'll see, upload your old config.php, and also upload your copy of settings.php. Then go to ./install/upgrade.php and make sure you choose 1.2.13 from the list.
As long as you have a database backup and file backup, you'll be fine if anything goes wrong.
Thanks Matt, I did look at the reply that looks to now be deleted, and wondered if it was the right thing or not simply because this would be a major upgrade.
What I shall do first of all is do an upgrade on my "test" forum and see how that goes before trying it on the "live" forum.
Good, that's the best thing you can do, just to get the hang of it.