When a customer logs in to your platform, their email address is passed as a value in the Intercom Messenger’s code (a parameter called email:).

You’ll need to make sure that you’re passing the customer’s new email address as the value here.

While you can update a customer’s email address through our API, this value will be overwritten on the customer’s next login if you haven’t made the necessary changes to the Messenger code outlined above.

That’s an unlucky implementation. I have a customer who contacted us through the messenger that his email has changed and that he cannot longer access emails send to the old address. I can change his email in our platform, but i have no option to tell him that i’ve changed it, because to use his new address, i’d have to tell him to login - what i can’t.