BLOG 12 March 2021

Avoid the Microsoft Teams “Islands Mode” Trap Part 1

I have been approached by many customers (both small as well as large Organizations) complaining about not so obvious and very confusing behavior between Skype for Business and Microsoft Teams.

I have been approached by many customers (both small as well as large Organizations) complaining about not so obvious and very confusing behavior between Skype for Business and Microsoft Teams. Those Organizations are already using Skype for Business (mainly On-Premises for their Enterprise Voice solution) and have started trials or pilots for Microsoft Teams.

Microsoft Teams is the successor of Skype for Business and is clearly the future for Microsoft Communication and Collaboration Technologies. Microsoft is actively pursuing all organizations to start using Microsoft Teams and preferably Upgrade from Skype for Business to Microsoft Teams.

Microsoft Teams Trials and Pilots usually start within a specific business unit inside an Organization, they focus on the collaboration part of Microsoft Teams but forget about the communications aspects of the Microsoft Communication tools. The Adoption of Microsoft Teams is usually growing organically as more and more people want to participate into the Microsoft Teams pilot.


The “Islands Mode” trap

This turns out to be a real problem as most companies just turn on Microsoft Teams without properly planning their journey from Skype for Business to Microsoft Teams. This results in unhappy users because of feature overlap and none interoperability between both communication tools.

Microsoft has made it really simple for Organization to Trial and Adopt Microsoft Teams as it is first of all Part of all Microsoft/Office 365 Enterprise Licenses (FREE if you already have Microsoft/Office 365) and secondly the default Upgrade experience when Organizations enable Microsoft Teams is set to “Islands Mode” which is ideal if you want to test it with a small group of people as you are basically not changing any existing configuration on Skype for Business and both tools run side by side for the small group of users.

The biggest problem with “Islands Mode” is that both Skype for Business and Microsoft Teams are as the mode describes “Islands”. They have nothing to do with each other and are completely disconnected, users will experience a set of inconvenient behaviors in both Skype for Business and Microsoft Teams. I would call this a lazy admin approach upgrade without caring about the End-Users, this mode basically puts all the responsibilities to properly communicate on the End-User.

Some examples for issues with “Islands Mode” include some of the following; All users need to be running both clients at the same time when users are trying to reach them in either Skype for Business or Microsoft Teams where Teams only talks to Teams and Skype only talks to Skype resulting in missed conversations going to the inbox whilst a user is active on the PC/Mobile but not actively running both clients at the same time. Presence in one client does not reflect the actual status in the other client as you can be in meeting in one and still available on the other one. Users will have to choose what type of meeting to send out to the recipients (either Skype for Business or Teams meeting) Teams users sending Teams meeting invitations to none Teams users need to join through a browser. There are many more examples to mention …

Ironically the “Islands Mode” also blocks the ability for a user to fully test Microsoft Teams as this mode still forces users to use Skype for Business for Presence, incoming PSTN calls and Federated conversations land in Skype for Business Only.  This mode is even more challenging for Skype for Business On-Premises Organization that use Skype for Business with Enterprise Voice.



Unpredictable Conversations between Microsoft Teams & Skype for Business in Islands Mode


Plan for “Upgrade Modes”

Microsoft has introduced “Microsoft Teams Upgrade Modes” to both streamline the Migration process and provide Interoperability between Skype for Business (both On-Premises and Online) and Microsoft Teams.  The Upgrade Modes concept removes the confusion for End-Users as Presence, Chat and Calling always go to one single client with predictable communications every time.  The idea for “Upgrade Modes” is that you can gradually introduce more features to users and have a predictable path for Upgrading to Microsoft Teams.

As it turns out there are not so many Organization that are using proper “Upgrade Modes” for Microsoft Teams, Organizations have problems understanding the “Upgrade Mode” concept and just turn on Microsoft Teams, resulting in failed Microsoft Teams Adoption and User un-happiness.



Introducing the Microsoft Teams Upgrade Modes


Note: “Upgrade Modes” can be applied to specific users, this means different parts of your organization can be in different Upgrade Modes at any point in time.  For example: While some users could be in Teams Only mode others can still be using Skype for Business with collaboration.

This is the list of Microsoft Teams Upgrade modes with just a little more background and guidance on how and when to use them:

  • Islands Mode: I already talked about this mode extensively, I hope by now you understand this is a mode you should never use in production.
  • Skype for Business Only Mode: This mode obviously only allows a user to use Skype for Business and has no Microsoft Teams functionality.  Most likely this is not a mode you want to pick for your users as you may want to look at the other modes too, unless you need this for users that cannot use Microsoft Teams. 
  • Skype for Business with Teams Collaboration: This mode is to use Skype for Business with Microsoft Teams for persistent chat in Teams, Channels, Tabs, Applications and Bots in combination with no change to the features or user experience for Skype for Business.  This mode allows you to ease in Microsoft Teams with no overlapping features so users cannot be confused.  This is highly recommended for most users not participating in the Microsoft Teams pilot that may require more complete feature set for Teams.
  • Skype for Business with Teams Collaboration and Meetings: This mode now enhances Microsoft Teams with a richer meetings experience compared to Skype for Business, while users are still using Skype for Business for all Chat and Calling experiences there are no overlapping features and users are now sending out Microsoft Teams meetings instead of Skype for Business Meetings.
  • Teams Only: This is the ultimate end state for the Microsoft Teams upgrade journey and now users are using Teams for all Chat, Calling, Meetings and Collaboration features.  Skype for Business will be in a locked down state and serve as a meeting only client for existing meetings or meetings from Skype for Business users.

Note: In “Teams Only” mode the Skype for Business the user has now been migrated to Teams. (The Skype for Business Server thinks the user is still using Skype for Business Online, the Server has no concept or knowledge of Teams.   Microsoft makes sure that all messages are routed correctly to and from Microsoft Teams by using the Skype for Business to Microsoft Teams Gateway in Office 365, this makes the interop between Skype for Business and Teams work.)



Predictable Conversations between Microsoft Teams & Skype for Business in any combination of Upgrade Modes (no Islands Mode)


Organization Wide configuration

Microsoft has a single global setting you can tweak to configure your entire Organization at once.  Setting the “Organization Wide Settings > Teams Upgrade Mode”.  If you are using Skype for Business On-Premises and want to Upgrade to Teams you may want to choose “Skype for Business with Teams Collaboration” for everyone and configure your Teams (pilot) users with a user specific upgrade mode of “Teams Only” if you can (keep in mind that Voice configuration may require other modes to be configured).  This way users will not get confused when you introduce Microsoft Teams in your Organization, users that get the Organization Wide setting are automatically configured with the right Upgrade Mode until they start using Microsoft Teams.


First configure the Org-Wide Settings 
(Organization Wide Settings > Teams Upgrade Mode)

Then select the appropriate Upgrade Mode for specific Users (in this example “Teams Only” but your configuration may differ) (Users > Username > Teams Upgrade)



I trust you now understand the value and necessity of the “Upgrade Mode” approach, don’t hesitate to start planning your Microsoft Teams journey today because someone will (eventually) turn on Microsoft Teams, you can better be prepared!


More information can be found through the following links.

Originally Posted on the Enow Software Blog:


Read more about Microsoft Teams “Islands Mode” Trap in part 2 of our blog!


Microsoft Teams Islands Mode Trap part 2 >

Johan Delimon



  • Teams Voice
  • Teams Meeting Rooms



  • Microsoft Teams & Skype for Business MVP, MCSM, Microsoft Trainer, Enterprise Architect & Community Leader
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