It would be nice that we received an e-mail about it though, instead a call from angry customers because our layout is messed up at the moment...
"Backward compatibility" isn't just words for us. Actually, we invest a lot to make sure that our new releases don't break custom changes & themes. Well, in some cases it really slows down our work, because we cannot simply change any Ecwid element to improve it. We need to make sure that all custom modifications that can be applied to this element will still work properly. Sometime, it's really a big challenge, but we understand the importance of this. Nobody will love if a custom modification stops working after the update.
Regarding the issue: the v10.2 didn't introduce any design changes that could break the page layout. So, we'd appreciate if you provided some more details.