After some discussion and debate, the Maven developers have agreed  to
replan the next release of Maven.
The original plans for Maven 3.4.0 were that it should consist of
effectively a no-op drop in replacement of Eclipse's Aether project (which
has been retired at the Eclipse Foundation) for the migrated code now known
as Apache's Maven Resolver. Additionally the plans called for some other
orthogonal changes around logging colourization and some launcher script
Due to some misunderstanding, there were quite a number of other changes
introduced which could be seen as modifying how dependencies and classpaths
get built. While we want to get these changes released as bug fixes, it is
also important to us to provide a clear progression of development. Some of
the bugs we want to fix require changes to the resolver code and the
developers feel it is important to mark the baseline of the migrated code
such that it should be a drop-in replacement for 3.3.9.
In that regard we have reset the master branches of the following GIT
repositories to the point in time that corresponds to the 3.3.9 release:
* git://git.apache.org/maven.git was reset to
* git://git.apache.org/maven-integration-testing.git was reset to
* git://git.apache.org/maven-resolver.git was reset to
If you have clones of any of these repositories you will need to update
them as the master branch has been force-pushed.
As there have already been issues closed as fixed in 3.4.0 and a number of
3.4.0-SNAPSHOT releases were distributed for user feedback, it has been
decided to burn the 3.4.0 version number as a signal of the reset. The next
release of Maven will thus be 3.5.0
We have a (mostly) agreed plan for the content of the 3.5.0 release 
(there are still some issues being decided on)
As all the content of 3.5.0 has already been developed on the old master
branches (which have been retained as the pre-reset-master branches) it
should be relatively easy to pull each of the agreed changes and merge
them. For this reason we hope to be able to cut a release candidate of
3.5.0 relatively quickly.
The next step will be agreeing the content of next release (which we hope
to have follow 3.5.0 after 6-8 weeks and will either be called 3.5.1 or
3.6.0 depending on the agreed content).
The drive is to get almost all the content that was in the pre-reset-master
released, but in a version history that makes it easier for users to
understand the impact and makes it easier for developers to identify the
potential impact of the changes.