I have released Check Quota 2.2 today, with help from Paul Lesniewski of SquirrelMail Development Team. With this release, all Check Quota versions prior to this one and Quota Usage plugin maintained by Bill Shupp and Paul are obsoleted. The two plugins are now completely and officially merged.
The biggest change in Check Quota 2.2 is complete support of SquirrelMail 1.5.2 branch. Other changes are mostly bugfixes and optimizations, as well as new language strings. This means, translations of Check Quota 2.x will not work for Check Quota 2.2, so they are removed from the plugin.
Please send your translations to the SquirrelMail i18n team from now on. You can also send them to me, and I will forward them to the translation team.
You can download the new release from the downloads page.