Refactor storage layer to allow for new repository filesystems using drivers. (Reviewed by Cynthia Shang.)
Refactor IO layer to allow for new compression formats, checksum types, and other capabilities using filters. (Reviewed by Cynthia Shang.)
The stanza-upgrade command provides a mechanism for upgrading a stanza after upgrading to a new major version of PostgreSQL.
Contributed by Cynthia Shang.