Reading the APM 10.8 HF@ readme.txt it states the following:
“PostgreSQL database 9.6.2 - The manual upgrade procedure from 9.6.2 to 13.4 is available, see the user documentation”
Can you provide us with the software and instructions for a manual upgrade?
Here is the KB Article-> APM 10.x - How to manual upgrade PostgreSQL 9.6.2 to 13.4 and higher versions?
https://knowledge.broadcom.com/external/article?articleId=228491#/