Puppet 4 reached End of Life on 2018-12-31. There isn’t an official support matrix for the FOSS components. For Puppet enterprise this can be found here. PE 2018.1 is the oldest currently supported version. It currently ships Puppet 5.5.8.
Vox Pupuli will remove Puppet 4.x from the metadata.json and from the Travis CI testmatrix after 2019-01-01. Our lowest supported Puppet version will be 5.5.8. This deprecation will be followed by a major version bump of each Puppet module. We won’t do releases just for this change, but rather follow our normal release schedule.
For the Puppet 3 deprecation we created a branch called puppet3 with the
legacy codebase. This created quite some hassle and confusion, so we won’t do
this for Puppet 4.