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Your LimeSurvey version: 5.6.68
Own server or LimeSurvey hosting: own server 
Survey theme/template:
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Hello, I have some questions about limesurvey 5.6 and I hope you can help me.
1) is it possible to deactivate the modification of users' emails by the users themselves in their profile?
2) my users connect via CAS authentication (auth_cas module). I would like the email field (retrieved from the ldap) to be updated each time the user logs in and not just when creating their account. Is this possible?
Thank you for your help