To everyone who is interested:

I have just upgraded my blog to Wordpress 2.3, and both Zenshow 1.4 and Zenpress 1.2.2 work just fine. I haven't fiddled with the tagging stuff in the theme yet, but migrating tags from UTW to the new built in tagging functionality was very easy.

This was a concern as WP 2.3 is a pretty major upgrade for some as it includes lots of new features and some major database improvements.

Bear in mind I don't fully integrate Zenphoto with my Wordpress as some have done, so I don't know what upgrading to WP 2.3 would do in those cases.