First of all, Bron Gondwana has done a great job over the course of a number of releases, to resolve some of the bugs in Cyrus IMAP that may have been around for quite a while -though most of them you may not have noticed.
Since Cyrus IMAP has been around since 1993 (give or take), it inherently contains legacy implementations of features or required functionality, sometimes to the tune of "good enough". Seeking further compliance with IETF approved RFCs and allowing for further development has spawned a 2.4 software series, with large amounts of code refactoring and cleanup, and the addition of some interesting features -more on those later.
Just this week, the Cyrus IMAP team has released cyrus-imapd-2.4.10.tar.gz. One day later, I've submitted the build to Fedora rawhide, so it should be hitting your doorstep soon enough. I plan to follow up on releases upstream with packaging more quickly and more agile in the future. Yours truly being the Release Engineer for Cyrus IMAP & SASL, as part of my work for Kolab Systems, I like how we have established a culture of release early, release often within the Cyrus IMAP project, and how core developers like Bron can make releases happen almost autonomously, while in between the last version in the 2.3 product series and the first version of the 2.4 series, a good couple of years had past.
Further endeavors include our 2.5 roadmap (which I admit could use some love), documentation (which I work on) and of course testers and developers are always welcome!
In the Cyrus SASL realm, we're working to convert the CVS repository to GIT. This takes a long time, since like Cyrus IMAP, Cyrus SASL has been around for quite a while. I must say we have done our due dilligance over the past few months on this one though, so I expect the repository conversions to GIT I've been doing to be approved soon enough.
Using GIT for the Cyrus IMAP codebase has proven to be a lot more attractive to a lot more contributors (since they can now create their own working copies and collaborate on those), and I hope we achieve the same level of success for Cyrus SASL.