Collation version mismatch
The error message
PostgreSQL collation version mismatch
might be caused by updating the host operating system's glibc, which is responsible for collation implementations, and which the database is using in turn. When collation versions between host and database differ, this may lead to the message above. Typically it doesn't occur in stable versions of host operation systems, but in test versions.
The database was created using collation version 2.36, but the operating system provides version 2.37.