In #249 testing for Python 3.4 was removed (together with Python 2.6 and 3.3). Due to some unfortunate events msgpack 0.5.6 landed in Fedora EPEL 7 (RHEL/CentOS 7) and broke borgbackup which uses Pyton 3.4 there.

Issue #249 contains some statistics which show that Python 3.4 usage was not that much lower than 3.5/3.6 (about 2.9% vs. 6.2% vs. 6.6%).

Is there any chance we could reintroduce Python 3.4 support in msgpack or did you encounter too many issues with that version of Python?