Exchange Online Tenants can Postpone Roaming Signatures

Microsoft Gives Tenants More Time to Prepare for Roaming Signatures

Announced in MC684213 (26 October 2023), Microsoft is helping customers who struggle with the introduction of roaming signatures for Outlook by allowing them to postpone the implementation in tenants. This is a good idea, but it’s sad that Microsoft has taken so long to sort out what seems to be a reasonably straightforward feature. First promised in summer 2020 (when I noted that signature management is complex), Microsoft’s development of the feature ran into problems and eventually in July 2022, they announced that roaming signatures wouldn’t be available until October 2022. A year later, we’re still struggling to deal with roaming signatures across the Outlook client family.

The background is that OWA stores its signature information as mailbox settings. This implementation makes it easy for administrators to check if mailboxes have signatures configured and if not, make the necessary changes. By comparison, Outlook desktop (for Windows) traditionally stores its signature information in Outlook profiles in the system registry. The implementation goes back to the earliest days of Outlook desktop, now over 25 years old, and is much more difficult to deal with in terms of configuring standard signatures.

The Solution for Roaming Signatures

Microsoft’s solution stores signature information for Outlook clients in a hidden mailbox folder (visible using the MFCMAPI utility). This is a good approach because it means that the same signature information is available to any Outlook client that connects to the mailbox.

However, roaming signatures cause problems for OWA because the Set-MailboxMessageConfiguration cmdlet used to configure the mailbox settings for OWA signatures doesn’t work when a tenant uses roaming signatures. In essence, when roaming signatures are active within a tenant, OWA ignores the settings configured with Set-MailboxMessageConfiguration. That’s unacceptable when customers invest a lot of work to develop PowerShell scripts to manage signatures for users. Naturally, these customers were very unhappy when they discovered that Microsoft introduced a new problem for OWA by addressing the roaming signatures issue for Outlook desktop.

The problem has been known for well over a year at this point and it’s unknown why Microsoft has been so slow to respond. Perhaps it’s an instance of when the solution for a problem has always seemed to be close at hand without ever being attainable.

New Organization Setting to Postpone Roaming Signatures

The latest initiative is that Microsoft has implemented an Exchange Online configuration setting called PostponeRoamingSignaturesUntilLater. If set to True (or 1), Exchange Online disables roaming signatures for OWA and the Monarch client. This means that PowerShell scripts developed to manage OWA signatures with the Set-MailboxMessageConfiguration continue to work.

Set-OrganizationConfig -PostponeRoamingSignaturesUntilLater $true

This setting only affects OWA and Monarch. It has no effect on Outlook desktop clients.

Many tenants can already update this setting in their tenant. Microsoft will complete deployment to all tenants by mid-November 2023. By default, the setting is False, meaning that Outlook desktop clients can use roaming signatures.

Note the PostponeRoamingSignaturesUntilLater name chosen for the setting. This is a postponement. Microsoft plans to make roaming signatures the norm for Exchange Online in the future, once they’ve sorted out the problems that currently make it difficult for OWA to deal with the data stored in the hidden mailbox.

The change gives tenant administrators control over a mess that Microsoft caused. It’s good because previously administrators had to file a support request to have Microsoft disable roaming signatures through some backend process. However, the need for such a

Microsoft says that the only way to disable roaming signatures for Outlook desktop, remains to apply a registry setting.

ISVs and Roaming Signatures

Many third-party signature management solutions are available for Exchange Online. When Microsoft updates how Outlook clients fetch signature data, the change impacts the ISV products. Microsoft says that they are now working to deliver API support for roaming signatures so that ISV products can manage signatures in the mailbox location.

Given the length of time Microsoft has been working on the roaming signatures problem, it’s curious that the API is not already available. But then again, Microsoft’s history of helping ISVs working in this space has been patchy with many issues in the past. I thought things had turned the corner in 2020, but that improvement doesn’t appear to have persisted.

A Hard Computing Problem

I know things are complex anytime you try and work with Outlook desktop. That’s probably one of the reasons why Microsoft is gung-ho to prepare the current client with Monarch. It takes too long to innovate, too long to change the UI, too long to do anything. Even so, it’s hard to understand why developing a new mechanism for roaming signatures can have taken quite so long. I guess it’s one of those hard computing problems!

---

Support the work of the Office 365 for IT Pros team by subscribing to the Office 365 for IT Pros eBook. Your support pays for the time we need to track, analyze, and document the changing world of Microsoft 365 and Office 365.