[root@cas cas-overlay-template]# vim build.gradle

    implementation "org.apereo.cas:cas-server-support-simple-mfa:${project.'cas.version'}"

[root@cas cas-overlay-template]# vim etc/cas/config/cas.properties
cas.authn.mfa.triggers.global.global-provider-id=mfa-simple
#simple mfa via mail
spring.mail.host=smtp.domain.fr
spring.mail.port=25
spring.mail.testConnection=true
cas.authn.mfa.simple.mail.from=adminmfa@domain.eu
cas.authn.mfa.simple.mail.subject=CAS MFA Token
cas.authn.mfa.simple.mail.text=Hello! Your requested CAS token is ${token}
##cas.authn.mfa.simple.mail.attribute-name=mail

#cas.authn.mfa.simple.time-to-kill-in-seconds=300
#cas.authn.mfa.simple.token.time-to-live-in-seconds=300
cas.authn.mfa.simple.token.core.time-to-kill-in-seconds=300
cas.authn.mfa.simple.token.core.token-length=6

cas.authn.mfa.simple.name=Email MFA
cas.authn.mfa.simple.order=0