There is a serious problem with PowerBuilder 2019 R3:
We worked successively with Oracle 10 via native interface, afterwards
we changed database profile to Oracle 19 via native interface, it worked
fine. Afterwards we wanted to return to Oracle 10 but PB writes
ORA-03134: Connections to this server version are no longer supported.
ORACLE_HOME and TNS_ADMIN are correct because SQL*Plus has
access to the both servers OK. What could be the matter?
Thanks.
Try doing a "TNSPING name_of_your_tnsname" from the command line.
That way you'll see the information of which oracle client is being found (since I assume you have both clients installed, the one for Oracle 10 and the one for Oracle 19c?)
Also check the bitness (32 or 64) of the the client used in the tns-ping