Apple updated Apple Remote Desktop Wednesday, both the client and admin versions. The patch notes don’t list anything specific other than the vague, “[this update] addresses several issues related to overall reliability, usability and compatibility.”
The client is showing up as an update through Software Update (on Snow Leopard) as version 3.5.1. The patch notes include a link to a KnowledgeBase article for the update that currently resolves to a 404 error page.
The client version (3.5.1) was downloadable through Software Update but isn’t otherwise mentioned as of this writing on the Download site.