AWS will stop supporting PostgreSQL 9.4 at the end of Jun, 2020. All Adobe Campaign Classic instances that are running on PostgreSQL 9.4 will need to be upgraded to PostgreSQL 9.5 or PostgreSQL 9.6 before that date. You will find below common questions about this upgrade and its impact.
AWS RDS PostgreSQL requires upgrade from time to time as it gets into End Of Life (EOL) and AWS stops supporting such versions. The PostgreSQL (v9.4.x) is running under EOL and AWS is going to stop its support by end of Jun, 2020. All Adobe Campaign Classic instances that are running PostgreSQL 9.4 will need to be upgraded to PostgreSQL 9.5 or PostgreSQL 9.6 before end of Jun, 2020.