SOA webservices not working after 12c ERP db upgrade

After upgrading  database from oracle 11g to 12c in Oracle Apps R12.1.3,  got a strange issue where SOA webservices- SOAP, REST  stopped.

The following url showed 404

http://host.domain:8000/webservices/SOAProvider/?testquery

The issue was resolved after adding  following line in sqlnet.ora

SQLNET.ALLOWED_LOGON_VERSION=8

Had to bounce Apache, oafm after that.