Native Microsoft Sync Technology Migration

Brass Contributor

Back in the end of last year, Microsoft announced that they are moving Outlook for iOS and Android from the REST API protocol to the Microsoft native sync technology, starting with Office 365 customers and then users.


Six months later, I have checked up on this (as the message centre post has disappeared) and my Office 365 users are still using the REST API but my personal account is using the native sync.


Could anyone else please confirm that they are also still waiting?


Thank you.


Link for details:



13 Replies

It's currently available for accounts, and it's the other way around - first, then O365 will follow.

I’m sure that said Office 365 accounts first, because they are the accounts that benefit from it the most.


Wording on the message center posts is not always the best. If you have an account added to the application, you should already see it using the native sync technology (go on the account settings screen, look at the bottom). 

It just doesn't make sense. It would benefit companies to have this before users.

This was announced on the 15th of November and since then, we have had two further announcements that rely on this change.

21/02/2019 (MC173895) Outlook mobile supports Teams Meetings
"The ability to create Teams meetings will be available to all Outlook mobile customers. For customers who have migrated to the updated architecture using the Microsoft sync technology, as communicated in message center post MC165218, we’re also making it easier and faster to join a Teams meeting by introducing a new Join button in calendar events."

05/03/2019 (MC175147) Outlook mobile supports Teams Meetings - updated roll out plans
"In addition, for customers who have also started to use the Microsoft sync technology for Outlook mobile (MC165218), we’re introducing a new Teams Join button in calendar events. This makes it easy to Join a Teams meeting and will be available for all coexistence modes as users could be invited to Teams Meetings even if they are not enabled to create Teams meetings themselves. Customers who are not using the Outlook mobile sync technology yet will continue to be able to join Teams Meetings using the weblink in the meeting description. "


We have now fully converted to using Teams and because we haven't switched over to using the native sync, Outlook mobile still shows 'Skype for Business' for joining Team meetings. Users are selecting this and wondering why it's not working.

I'm going to raise a support ticket with them directly to get this resolved.

That was a waste of time. They seem to know less about this issue than I do!

@Vasil Michev 


Q: As a tenant administrator, can I control which of my users will be migrated to the native Microsoft sync technology?

No, the migration to the native Microsoft sync technology will be on a tenant-by-tenant basis and not a per-user basis. While the tenant selection order for migration is random, we are being deliberate about migrating Office 365 mailboxes first. If you are a customer operating in a hybrid configuration where a portion of your mailboxes remain on-premises, the on-premises users leveraging hybrid modern authentication will be migrated to the native Microsoft sync technology at a later date. This means that your Office 365 users will migrate to the native Microsoft sync technology, while the on-premises users continue to use the REST API to connect to Exchange Online.

@Anthony Russell 


For Outlook mobile, major feature deployment operates with a staggered rollout where we begin with consumer accounts (if applicable) and then deploy to commercial accounts like Office 365. Our primary focus for commercial accounts was moving Government Community Cloud. Now that's complete, we'll be focusing on the remaining O365 tenants.


As to the text you highlighted, you're taking it out of context from the rest of the paragraph as we're migrating O365 accounts to the Microsoft sync technology before we migrate on-premises Exchange accounts leveraging hybrid modern auth.

@Ross Smith IV 


Not sure what you mean. I can see that the paragraph mentions that on-premises hybrid accounts will be migrated at a later date, but this does not affect us as we don't have any.


The statement is clear to me that Office 365 accounts will be migrated first. I understand that GCC accounts need to be given priority, but consumer accounts?


My main issue here is that now we have been pushed to use Teams, we need to get it working as expected. At the moment, it doesn't.

@Vasil Michev When checking Outlook app account settings, what text should we expect to see for the new native sync technology?

My work account (cloud-based but in hybrid setup) says "Microsoft Sync Technology" so I'm not sure if that's old or new.



As per your work account, the text at the bottom of the account would say "Microsoft sync technology" which my personal account does, but not my work 'cloud only' account. According to Microsoft, hybrid accounts should be last to migrate. So your experience has also proved this to be wrong.


I raised a support ticket and, as usual, as soon as I mentioned the word 'Mobile' I started getting links to the iOS support page. After my "NOT SO FAST BUSTER" reply, they then said that the Team integration in iOS is not ready and I would have to wait. So even though they pushed us to migrate to Teams, stating it was feature ready (i.e. matching with SBF) it in fact is not.


This combined with other problems we are having with teams (SIP appearing in emails addresses in Outlook desktop) I've now told them to close the ticket and we will use an alternative online meeting service until Teams matures. 

@Anthony Russell - we're in the same boat and have a case open.

best response confirmed by Anthony Russell (Brass Contributor)

It seems we have now been converted today, as it now shows 'Microsoft sync technology' in the account info and the 'Teams Meeting' option shows up in Outlook mobile.


Running the PowerShell command shows that not all users are using it yet, but I have noticed that my device is showing twice. One for 'REST' and one for 'Outlook'.




Also notice that Outlook mobile on iOS got updated to version 3.24.1 overnight. Coincidence?

We've now migrated all O365 tenants to the native Microsoft sync technology.