Jira 8.13.12 officially supports PostgreSQL 12 but ATST health check fails with a following warning:
PostgreSQL 12 is not supported. You should migrate to a supported database version.
- run Jira 8.13.12 with PostgreSQL 12 as a database
- login as an admin
- navigate to system -> Troubleshooting and support tools
Supported database health check is green
ATST produces a warning about unsupported database
Currently there is no known workaround for this behavior. A workaround will be added here when available