14.04 was certainly not abandoned. That’s not how LTS releases work. When 16.04 gets a stable update to the applet, then it will almost certainly be backported to 14.04.
I’m not a Ubuntu-MATE developer, mind you. But that is usually how LTS releases work; i.e. when a new version of the distro becomes available, your development trunkmoves to the new version and you only backport stable package updates. You do this to ensure the stability of the older version that is still under the LTS period.
Meanwhile, this is not a problem with Ubuntu MATE 14.04, or 16.04. Currently the update to the weather applet doesn’t even formally exist in 16.04, since it requires a non supported update to MATE 1.14.1. So it’s not even as if 14.04 was being ignored. Following that reasoning Ubuntu-MATE 16.04 was being abandoned to. Instead, what this is, is simply a matter of waiting until the MATE project releases a stable update to the applet that can then be backported to MATE 1.12; which then can become available to both Ubuntu-MATE 14.04 and Ubuntu-MATE 16.04 without the need to update MATE to 1.14