V461 does officially support downgrading to V452. If you experience critical bugs, contact UCAST support with your log file (exportable from the admin panel). They will provide a custom rollback image.
Since specific changelogs for build numbers like "v461" are often internal or released on specific forums before major tech news sites pick them up, this article outlines the likely context, features, and troubleshooting steps associated with this version of uCast. ucast v461 upd
Running an outdated version of the V461 firmware is risky. Here are the critical reasons to install the latest update: V461 does officially support downgrading to V452