https://bugs.winehq.org/show_bug.cgi?id=51361
--- Comment #1 from Rafał Mużyło galtgendo@o2.pl --- ...to check the trivial: when you've upgraded libxml2 did you upgrade both 64 *and* 32 bit ?
Does WINEDEBUG=loaddll offer any hints ?
Going by the build system, there shouldn't be any changes between those versions that would break ABI...