zanshin-next 0.2.1-1074-ge570d19 doesn't seem to be able to synchronize the tags and contexts over things like CalDav (owncloud) because these are only stored in the local akonadi-tags. At least I can find no traces of them on a different PC after the sync. Reproducible: Always
I confirm this is the case. We have no good solution for that at the moment. I plan to revisit that topic around 0.5 not before.
This is still an hard one to crack and won't make it for 0.5... hopefully will be addressed in 0.6.