When using Dual Write and Global Address Book Solution, there is a lot logic involved by Microsoft, copying data between Party Electronic Addresses and the Contact or Account form. By default you can select between different types, e.g. Phone, Email Fax Twitter, etc. and specify one of each type as primary.

When selecting phone, there is also the possibility to define the number as mobile using an additional checkbox.

The default logic for Primary phone is to sync the number with "telephone1" (Business phone) column. Unfortunately, when adding primary and mobile to an electronic party address, the number will still be synchronized to "telephone1" (Business Phone) and not to the also existing mobilephone column.

Due to the fact that the mobile phone is for many use cases the primary number and with the sms feature of release 2023 wave 1 even gets more important, it would be helpful to either synchronize the combination of primary and mobile to the mobile phone column or to get rid of the mobile checkmark and add the mobile phone to the type choice and allow setting the primary checkbox so that both columns - telephone1 and mobilephone - will be filled.

At the moment the feature is not usable for mobile usecases.