Why I am not able see Email encryption feature in CAS version 3.1.5.1
CAS running version 3.1.5.1
Feature is enabled in higher version of CAS
Need to upgrade the CAS appliance to 3.1.9.1 or later versions (3.2)
Ref link :
Can be enabled with the CLI command
server-settings encryption type Email (SMTP) Encryption [TLS | StartTLS| None]
OR
Settings > Alerts > E-mail > Encryption Type