To OP, and others: read the
AMA, that I posted in these forums a month ago.
There are several references to TH14, most replies aiming at a release this year, but some also hint that its design is still a work in progress. Moreover, as usual with this game, releases are done when the content is ready, not before.
There is a planned update coming in April, but its content has not been discussed yet. The wording ‘major’ used by Darian means it is more than just a balancing act (defense or offense levels); but it could also be other content, like a new feature (CG or LL as past example).
If previous years are indicative, expect 4 updates this year. But this depends if their content becomes available.
Edit: an
example of major update in April, not involving a new TH... and that was major
... that was 7 years ago!