In case of assistance submit a new case through Support Central > Case Management to request techincal help in updating the TLS1.2 High Ciphers, with the subject title "BMC Helix Client Gateway enable TLS1.2 High ciphers- Assistance Request".
NOTE: Please attach kwic-config.xml from the on-premises client gateways while raising a support case
Enabling TLS1.2 High Ciphers can be performed at anypoint of time,follwed by a Service restart of the on-premises BMC Helix Client Gateway.