I'm compelled to nitpick, sorry.

It's a UX/UI issue. It's possible to lose access to a wallet by failing to back it up before switching to a later non-backwards-compatible client which, if for some reason proves undesirable to the user, causes them to switch back to the old client. That's when they discover that the new client automatically upgraded their wallet to the new db format which cannot now be read by the old client. That's why the advice (for distributed binaries, i.e. OS X/Windows) is to link against 4.8.

It may be an edge case and it may be perceived as a userland issue but I categorise it as a development UX/UI issue because of the underlying loose assumption of technical competence on the part of the user without an accompanying specification of the minimum level of technical understanding required to perform basic wallet/chain maintenance operations. (A principle lucidly expressed by my father as: "If a man doesn't understand, it's because he hasn't been told properly.").

Cheers

Graham