I was going to put M4 out today. However one of my "procedures" if you will is to first "divebomb" it on my own server. Unsuprisingly bugs that weren't apparent on my test servers with bogus data were very apparent with real data. I just committed fixes for bogus mailboxes (when someone sends email@example.com a mail in hopes of guessing) which were causing a looped redelivery. Moreover a fix for pop which was depending on natural database ordering for dele command. And locking finally works correctly with POP in JBMS (I don't think M3 had that right either). I also commited all the stuff necessary to do the "ant dist" target as of today. (complete with unwrapped/exploded par files...thanks to Bill Burke for his answering questions there and leading me to give it another try)
So far my server is running pretty nicely after the latest commits (today).
There were a few more patches to the store affecting memory utilization. If all goes well, I'll cut the release in a few hours.