Suddenly see "get the latest update to continue using skype" in Skype. Will it stop working by April 2020?
Are you required to update Skype or it will stop working?  Yes.

From their Support FAQ


  Do I have to update to the latest version?
  Yes. Support for Skype version 7 and below will end on November 1, 2018 on desktop devices and November 15, 2018 on mobile and tablet devices. When support ends, we’ll begin requiring updates to the latest version


I know this first hand as I had a VM with an old snap shot that had an out of date Skype client - 8.1, I believe. It didn’t connect until I updated it.  Additionally, I ran across this thread on the Microsoft Forums.


  Why does Skype stop working after MINOR update?
  For example, several days ago I updated Skype to version 8.27 at several computers.  Today Skype stops running at those computers because version 8.28 was releasing.


Generally speaking, Microsoft has changed its update policy to make sure everyone is running the latest and greatest.   Most of the time it works, but I still prefer to be in control.  I can’t tell you how many times I updated my laptop the night before a presentation only to be presented with an updating screen just as I was about to present or demo.