After migrating to Oracle 21c,my PL/SQL Version 13.0.6.1911 (64 bit) refuses to execute a query that worked fine on 12c,18c and 19c.
##'A query with objects requires OCI8 mode but OCI7 mode is used"##
## Preferences: Use OCI7: False ##
This happens with InstantClient 12.2 and 19.1 64 bits Clients.