An update to the Social Groups system for XenForo 2.x has been released. Those that have purchased this add-on, please log into your account to download this update.
Fix - Error when attempting to access a discussion from a deleted group
Fix - Template modifications to account for changes to Ui.X2 style (version 220.127.116.11)
UPGRADE INSTRUCTIONS FOR Ui.X2 STYLE USERS
1) Take your site offline (Admin->Setup->Options->Board active)
2) Disable the Social Groups add-on
3) Upgrade the Ui.X2 style
4) Upgrade the Social Groups add-on
5) Re-enable the Social Groups add-on
6) Put your site back online
Those instructions are for Ui.X2 style users only. Others need not do anything other than a regular add-on upgrade.