Hi Rinkesh,
the product documentaion can become your best friend ;-)
We don't have any specific post-upgrade procedures from the BSM side after updating the database,
however you need to check whether or not there are notes or remarks in the documents for a certain product combination.
Running the Configuration Wizard is usually not required, in the end the DB update should be transparent to the application.
For BSM 9.26 with Oracle 12c you can read in the Database Guide, Chapter 8: Oracle Server Deployment Overview
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Note:
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l If you install Oracle 12c:
a. On the Oracle database machine, go to oracle/product/<oracle version>/db_001/network/admin
where <oracle version> is the Oracle version you are using, for example 12.1.0.2
b. Locate sqlnet.ora and add the line SQLNET.ALLOWED_LOGON_VERSION=8.
c. Save the file.
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Greetings
Siggi