From Cisco Jabber Guest Administration, choose Services > Passwords.
Check Complexity check if you want passwords to meet the following requirements:
Passwords must be eight or more characters in length.
Passwords must include three of the following characters:
At least one uppercase letter
At least one lowercase letter
At least one number
At least one symbol
For History size, enter the number of passwords that are remembered. For example, if you enter 3, the user's previous three passwords are remembered. If a user tries to change the password and reuses one of the previous three passwords, the user is prompted to specify a different password.
For Maximum failed sign ins, enter the number of sign in attempts allowed before the user account is locked.