The PostGIS project strives to support each minor version of PostGIS for 2-4 years after initial release and at the very least until the lowest PostgreSQL version supported by the PostGIS minor version is EOL'd. Refer to PostgreSQL EOL policy for details. Support for a new PostgreSQL major version generally starts at the newest stable release version of PostGIS available at the time of the PostgreSQL major version release. We may on occasion introduce compile support for a newer PostgreSQL major version in the previous micro version to allow easier PostgreSQL pg_upgrade migrations. Each minor version of PostGIS may introduce features that are only exposed on the latest version of PostgreSQL, Proj, GEOS, or GDAL. While the PostGIS version may work on lower versions of PostgreSQL, GEOS, GDAL, and Proj, enhanced features may be disabled on the lower versions.
For further details, refer to our compatibility and support matrix.