PostgreSQL Backward Compatibility
Summary: Backward compatibility of database versions is critical, as it directly impacts the availability, continuity, and overall efficiency of business systems, and is necessary for the success of a database product. When you get used to using some successful database products, you may not feel that they exist, because it has become like air and water, making you feel that database products are supposed to be the way they are. However, if you choose to use a bad database product, you will feel like you’re always running into problems because of the lack of backward compatibility of the versions.