libical has inherited two bugs from the Evolution fork of libical:
The main effect is that in large parts of the world (Western Europe, Australia, South America, Asia) the transition from summer saving time to winter time will not be calculated correctly.
I did a diff between tzutil.c in Evolution and in libical-0.32; the fix should be easy to merge.
Sorry for not reporting this earlier! Please don't shoot the messenger. A while ago I asked on the Evolution hackers list how their fork of libical is related to the sf.net branch but didn't get a response.
My own interpretation now is that Evolution's copy is an old fork and that the real development takes place here; will take that into account for future bug reports.