RTB v3.3 has been released. I honestly can't remember what I've changed since v3.2 since it's been such a long time, but there are lots of bug fixes.
The main new feature is the add-on grouping. This can be accessed either via Start a Server > Add-Ons (the Groups button) or by clicking the "Groups" tab in the Your Mods section of the Mod Manager. Grouping allows you to create a group which contains specific add-ons and you can then enable/disable these groups from the Add-Ons menu as usual.
Just restart/open Blockland to get the update.
You can post any bugs/issues/questions in this thread or on our forums at http://forum.returntoblockland.com/