7.1.5 --> 7.2.x upgrade: what do I need to be aware of/watch out for?

I’ve been working on our system for a couple of months, and it’s in 7.1.5 currently as 7.1.x was the current version when we got started. 7.2.x obviously is now current and I’d like to upgrade but I’m seeing some posts from others that have done this and things haven’t gone as smoothly as one would hope.

Our app uses the Calendar control which it seems was very much changed. There are also quite a few deeply nested/complex screens.

So… what should I be aware of in contemplating this upgrade?