Vanilla 2.6 is here
! It includes security fixes and requires PHP 7.0. We have therefore ALSO released Vanilla 2.5.2
with security patches if you are still on PHP 5.6 to give you additional time to upgrade.
Let users choose which theme they want to use
This would be a nice option to have, and it's a common feature of other forums. I haven't seen any addons for this yet either.