Ubuntu Xenial os out for a couple of months now. Some Ubuntu Touch devices like the M10 are already running the Xenial base. But e.g. the Aquaris E4.5 are still running Vivid (15.04) base. When will be a switchover? This should by the way be technically possible, right?
I believe this thread answers the question.
On April 22, 2016 Łukasz Zemczak wrote:
As already mentioned in a few landing e-mails, the baseline switch from vivid to xenial is our near-term plan for stable channels. But please remember that it's not an easy task. When we were switching our baseline from 14.09 (ubuntu-rtm) to 15.04 long time ago it took us a few months to stabilize the phone again. With xenial introducing the g++ ABI break (and a few other nuances), the whole process could take even longer since there's more things we need to consider during the switch.
The most difficult part is that we can't only concentrate on one front, meaning: we can't just drop everything and just work on getting xenial (devel-proposed) into working shape as our current focus needs to be on the stable devices (vivid-overlay). That being said, we will be preparing something similar to a 'task force' that will be taking care of moving the xenial initiative forward. It's really hard to give a firm schedule here - with this we still need to wait a bit.
All this means the next few OTAs will still be vivid-based with our development focus on vivid, but then we intend to switch to xenial for future devices.