Before each major release, a pre-release phase takes place for some time during which you are invited to try the source code of what will be the next major release. Pre-release code has been already tested a lot, it is considered to be stable, but still remains the possibility that it will not compile properly for a particular system or that some bug has silently passed all the tests.
If you wish to participate in the current pre-release phase (and you are very welcome!), thanks to:
The pre-release mailing-list's purpose is for you to share your feedback about problem you have met and to be informed of fixes and/or new versions of pre-releases (it not archived)
Pre-release phase for release 2.7.0 has completed March 24th, 2021