I've got a MySQL server running version X (X=5.0.22) and for misc. reasons the underlying hardware needs to be upgraded. Give that this is going to be done, how risky would it be to also upgrade the MySQL version at the same time to version Y (Y>=5.1.6)? In particular, is there a list of things that can break in more or less silent ways (as opposed to the DB restore falling over on it's side)?
I'm need an answer for my specific values but a more general matrix of breaking changes/things to worry about would be better in general.
Also I have very little DB admin experience and even less experience on this DB so a fairly precise checklist of thing to look for would make things much easier for me.
Links I've found so far: