stable release of xwiki?

I am using 0.9.840, and I seem to be running into all kinds of exceptions and problems. I tried the mail plugin and got it working, but the registrations do not survive a restart for some reason. Anyone know of a wiki that has 1. Email notification 2. Locking and timeout of editing(I miss the counter in MoinMoin that says 10 minutes left, 9 minutes, etc). XWiki does not seem to timeout 3. pdf capability 4. roadmap to have WYSIWYG and all the normal versioning, diffing, etc. thanks, dean