Microsoft is deprecating Service Number usage in Teams Caller-ID policy.

Have you configured Teams Caller-ID policy to mask your user phone number or provide an alternative caller-id using Microsoft Service Numbers? Then it's time for you to migrate the Caller-ID configuration from Service substitute to Resource Account Substitute.

By default, the user with the LineURI attribute updated or assigned a dedicated DID/DDI number will display as caller-id and your registered CNAM as the display name using the Global Caller-ID policy.

If you have created a custom Caller-ID policy to block/provide alternative caller-ID using a Microsoft Service number e.g, Conference Number.

Microsoft depreciating CallingIDSubtitute attribute having "Service" starting mid-Feb'2023.

You must configure the Microsoft Teams "Resource" Account in the CallingIDSubtitute attribute.

New Caller-ID Policy -

You will get an error when you create a new Caller-ID policy with the Service CallingIDSubtitute. User latest PowerShell module 4.9.3.

Migrate Existing Caller-ID policy -

Resource substitution uses the phone number of a resource account associated with an Auto Attendant or Call Queue. It supports Calling Plan, Direct Routing, and Operator Connect phone numbers.


You need to create/use an existing Teams Resource account assigned Microsoft Teams Phone Resource Account License (a.k.a Virtual User License) assigned the required phone number from either Calling Plan, Direct Routing, or Operator Connect.

Create a new caller-id policy with the existing resource account phone number via PowerShell -

$ObjId = (Get-CsOnlineApplicationInstance -Identity contoso-regional-caller-id@contoso.com).ObjectId

New-CsCallingLineIdentity -Identity Contoso-Regional-Number -CallingIDSubstitute Resource -EnableUserOverride $false -ResourceAccount $ObjId -CompanyName "Contoso"

Find all existing users who use the old caller-id policy and export the details in a CSV file then, you can use Grant-CsCallingLineIDPolicy to assign the policy.

Modify the existing Caller-ID Policy that has the Service CallingIDSubtitute attribute via TAC -

If you have an existing Caller-ID policy, you can modify the policy from "Service" to "Resource" and choose the correct account with the correct Phone number assigned.