> On Nov 18, 2020, at 08:05, Stephen Haddock <haddock(dot)stephenm(at)gmail(dot)com> wrote:
> When upgrading an older version of postgres, version 8.4 for example, to a newer version such as 9.6, does the data have to be migrated immediately?
Yes. You cannot run binaries from a newer major version of PostgreSQL on a cluster that was initialized with an older major version. You'll need to do a pg_dump/pg_restore, or use pg_upgrade to create a new cluster.
--
-- Christophe Pettus
xof(at)thebuild(dot)com