For 4.0.0, here a design for a release message. When do you plan 4.0.0, I see on bug list you mention Friday somewhere?
Version 4.0.0, the "The Miracle of Birth, has been released. This is a major release, don't upgrade before verifying your system can run it.
As one of the very first big ($5.4 million ), multi-platform (Linux, Windows, Mac OS X, ...), non-Gnome GTK applications, Gramps makes the jump to GTK 3. At the same time python 2.7 and python 3 are supported, though the last must still be considered experimental. Gramps 4.0 further uses distutils for distribution, so the install sequence is changed.
The Gramps developers have tried to make Gramps 4.0 as identical as possible to 3.4, so no data changes are done, nor are there big interface changes. In other words, a .gramps backup file of version 4.0 will open without problems in Grarmps 3.4, giving users the possibility to fully try Gramps 4.0.
Don't be mistaken though, a huge amount of code is new and changed! In order to bring this release we thank the many developers who helped the GTK support on Mac, Windows and Linux forward. Note however, Gramps 4.0 will only work on a top of a very recent sortware stack. A Windows installer will probably not be available soon. In Linux current distro's don't contain the optional packages in the form Gramps 4.0 needs. All this should make clear you can safely keep using version 3.4 and wait for packagers to catch up. People who cannot upgrade the required components but want to use Gramps 4.0 should use it in Virtualbox 
Before you upgrade, make sure your family tree data is secure. The best way to do this is:
- Start Gramps 3.4
- Open your family tree
- Export the family tree to the gramps xml format or the gramps xml package
format (which includes your photographs and other media files
associated with your family tree data). Export your tree via menu Family Trees->Backup....
- Close this family tree and repeat the above steps for any other family trees you have
- Keep the resulting file(s) in a safe place