Copying Transparent Encryption Oracle Wallets
If your database uses Transparent Data Encryption (TDE) and a software
        keystore, and you rely on the sqlnet.ora parameter
            ENCRYPTION_WALLET_LOCATION to locate the TDE software keystore, then
        ensure that the new release sqlnet.ora has a proper configuration. 
               
Note:
This procedure using sqlnet.ora to configure keystores is
                    deprecated. Oracle recommends that you use the instance initialization
                    file-based approach using the WALLET_ROOT and
                        TDE_CONFIGURATION initialization parameters. After the
                    upgrade, review and configure the WALLET_ROOT initialization
                    parameter.
                     
If you use the sqlnet.ora file to configure keystores, then you
                must copy sqlnet.ora and the keystore file manually to a keystore
                location outside of the Oracle home. Wallets should be stored in a location outside
                of an Oracle Home. If you move the wallet, then you must update
                    sqlnet.ora before starting the upgrade. For auto-login wallets,
                you must also copy the cwallet.sso file manually to the new
                keystore location.