For GOS 20.08 and GOS 6.0 new patch levels are available:
https://www.greenbone.net/en/roadmap-lifecycle/
GOS 6.0.12 fixes an issue with upgrading certain GSM hardware setups to GOS 20.08.
GOS 20.08.1 includes several fixes that did not make it into the initial GOS 20.08.0 release.
Please refer to the Roadmap & Lifecycle page for a full list of changes in each case.
In total GOS 20.08.1 covers 5 improvements and GOS 6.0.12 covers 1 improvement.