I've been asked to retrieve, and then carry out a bulk update of the phone number displayed on the Contact card in Microsoft 365 (e.g. Outlook). I know how to get the Mobile phone and Business phones fields from Entra:

https://graph.microsoft.com/v1.0/users/?$select=mobilePhone,businessPhones

I have found, though, that there are users with a Mobile number displayed on the contact card in Outlook, where the telephone fields in Entra are blank (and the above request returns empty results). I've searched through the "user resource type" documentation, and there don't appear to be any additional phone fields.

Could anyone point me to a way to do this, please?

Thank you,
Rob