If there is any exception in the logs please post that, there is no limitation introduced in 8.11 regarding Postgres.
We are facing the error when we add the Postgres Translator.
The exception faced is IllegalStateException("version not set").
The start method in org.teiid.translator.jdbc.postgresql.PostgreSQLExecutionFactory is checking the product version which is null when the translator is added.
We can see that the getVersion method in JDBCExecutionFactory was modified to throw an exception recently.
Is there any step needed before adding the translator/any other step needed to make this work after this change ?
The issue may be that TEIID-3483 moved the setting of the version to be on just the initial connection attempt int the obtainedConnection method (so that it happened as early as possible). However if you are overriding getConnection or there is a connection error with the initial attempt then the version will not get set. This needs some additional refinement.