What format do I use for IBM Verse People's phone numbers to integrate with Caller ID using the Call Directory Extension?

IBM Verse sanitizes all phone numbers before updating the Call Directory Extension, so any phone number format is allowed, as long as the phone number includes a country code. For example, all of the following phone numbers will be sent to the Call Directory Extension as 12345678901:

+1 (234) - 567 - 8901
Note: Country codes are required for integration with iOS Caller ID to be successful. For example, +1 (234) - 567 - 8901 is valid, but (234) - 567 - 8901 is not valid.