https://lists.torproject.org/pipermail/tor-announce/2019-January/000171.html
FWIW, in the ChangeLog (in the source, sorry) it mentions:
As a reminder, the Tor 0.3.4 series will be supported until 10 June
2019. Some time between now and then, users should switch to the Tor
0.3.5 series, which will receive long-term support until at least 1
Feb 2022.
So we should consider moving to 0.3.5 "soon" :).