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...
CFinch please note that there is no anymore term "new Outlook", there is the "Outlook for Windows", and "Outlook classic" 😛 , anyhow it does not have nothing with signatures.
Regarding Microsoft saying there are no plans to support roaming signature management in Microsoft Graph API, while having most of other settings is very strange.