That depends. Jolla has never officially acknowledged anything. It was a community member who found "something". Even if Jolla had bothered to respond, the best we could hope for is, "we have changed X, you must now all update your code to work around it."

The way I see it is, application X worked before the OS update. Application X did not change but it does not work now. What broke it?

It is called backwards compatibility, in case you were wondering But hey, this is OT The workaround in that thread should do the trick indeed.