Since Microsoft released “Roaming Signatures” it has been expected that there will come support for this in the Graph API, so that external applications, for instance IAM systems, can update signatur...
The https://learn.microsoft.com/en-us/powershell/module/exchange/set-organizationconfig?view=exchange-ps#-postponeroamingsignaturesuntillaterhttps://learn.microsoft.com/en-us/powershell/module/exchange/set-organizationconfig?view=exchange-ps#-postponeroamingsignaturesuntillater also refers to the upcoming API:
We're working on API support so admins and ISVs can configure roaming signatures directly.
It would be helpful with an ETA.