One task in the 1.10 release process is reviewing API changes.
One way, that I use myself, is to take a library at a time and compare the 1.9 and 1.10 public headers, looking for procedural errors (e.g. how new and deprecated APIs are marked up, undocumented parameters, etc.) and for possible semantic problems such as changing one part of the API but not changing a related part in the corresponding way.
Another possible approach is to look for compatibility breakage by running the 1.9 client and test suite against the 1.10 libraries, and indeed different client/server version combinations.
Can anyone volunteer for any of this? - Julian
