Re: BUG #16843: pg_upgrade from 12.5 to 13.1 with extension plperlu failed

PG Bug reporting form <noreply@postgresql.org> writes:
> In the upgrade process with pg_upgrade ( as user postgres) following error
> occured:

> pg_restore: Error: could not execute query: ERROR:  Language »plperlu« does
> not exist
> The statement was: CREATE OR REPLACE PROCEDURAL LANGUAGE "plperlu";

It looks like you neglected to install the plperlu package
(it's probably named something like postgresql-plperl).

            regards, tom lane