Currently I can just confirm that I have the same issue with my OpenHAB system and Bosch SmartHome Controller after todays update.
In the logs I get this error
[ernal.devices.bridge.BoschHttpClient] - Pairing failed with exception null
A breaking API change was announced and the main branch contains already a fix, see [boschshc] Upgrade to REST API version 3.2 · Issue #15053 · openhab/openhab-addons · GitHub.
Update:
The 3.4.x branch contains the fix
The 3.4.4 tag does not contain the fix
I have no information when a new 3.4.x version will released. @laursen Do you know more?