I would add LinuxQuestions to the list of places you would send the release announcement to if I were you. It probably has the biggest user group of any dedicates Linux forum.
As for updating from 3.5.13 to 14 these things are never easy and, for Debian based distros, I would normally recommend a clean install after a proper backup is done. I know with the MATE Desktop Environment, which I also use, each upgrade has teething problems when upgrades are done but are do not occur with clean installs. That is why when I finally release Cobber (about 1 months time hopefully) what I release Cobber Stable with is what it will remain released with but I may backport newer releases for those who are willing to work through teething problems.
Cheers.