Are you sure that 9.x refuse to open an index first created in 7.x? I thought that strict policy was only needed in 8.0 due to a particular lossy data structure change, and that 9.x is more lenient?
Jan > 24. aug. 2023 kl. 22:38 skrev Shawn Heisey <apa...@elyograg.org>: > > Version 9 behaves the same as 8. If the index was ever touched by a version > before 8.0, version 9 will not read the index.
