Does it make sense to upgrade to a newer PostgreSQL JDBC driver?
You should always ensure that the JDBC driver is at least as new as the back-end server.

PostgreSQL's catalogs change between major versions, and other details like the bytea quoting method, string escaping features, etc have also changed over time. PgJDBC contains compatibility code to cope with this by querying the server version. If you don't use a current driver, you may have issues with some features, particularly JDBC metadata access and bytea fields.