OpenBh 5.5.1 is based on the OE-Alliance 5.5.1 core.

So what is different in OpenBh 5.5.1 then?

The main change from version 5.4.1 to version 5.5.1 has been changes to oe-alliance-core branch 5.5.1. The OE (Open Embedded) core on which the image is built has undergone major changes, updates and fixes. Version 5.5.1 uses Python version 3.12.8.

Whats New:

OE-A 5.5.1
Python 3.12.8
Gstreamer updated to version 1.24.10
Switch to udev (userspace /dev).
If your favourite plugins no longer work, you will need to contact the plugin authors to ask them to update their plugins for Python3.12.8
*** You can not online update from 5.4.1 to 5.5.1, you must reflash (you can do this using image and backup manager and then restore your settings backup) ***

Apart from the above you should not notice many differences between previous OpenBh 5.4.1 and OpenBh 5.5.1 images.