Coexistence Mode Teams: The Best Guide (2023)

This is a complete guide to learn about coexistence mode teams.

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Coexistence mode teams

As an organization with Skype for Business starts to adopt Teams, administrators can manage the user experience in their organization using the concept of coexistence “mode” which is a property of TeamsUpgradePolicy. Using mode, administrators manage interop and migration as they manage the transition from Skype for Business to Teams. A user’s mode determines in which client incoming chats and calls land as well as in what service (Teams or Skype for Business) new meetings are scheduled. It also governs what functionality is available in the Teams client.

Using TeamsOnly mode in combination with other users in Islands mode is not recommended until Teams adoption is saturated, i.e. all Islands mode users actively use and monitor both the Teams and Skype for Business clients. If a TeamsOnly user initiates a call or chat to an Islands user, that call or chat will land in the Islands user’s Teams client; if the Islands user does not use or monitor Teams, that user will appear offline and will not be reachable by the TeamsOnly user.

• A Findtime doesn’t support auto scheduling if you are in Teams only mode.
• Team only – only has SfB client to attend SfB meetings.
• Xx mode with NOTIFICATIONS – adds a purple banner in the SfB client.
• Skype for Business only mode – ignore – only used.
• Islands – default – for everyone.
• Teams usage across the organization has tipped the balance then look at an organization wide switch to Teams only.

Suggestion

• Islands mode for IT and large EA group
  • When would they get switched over to Teams only
  • We cannot change them to Skype with Teams Collab only as we are taking away some Teams functionality
• Skype with Teams Collab for entire Org
  • 2-3 months later – switch to Teams only
• Interop
  • Islands using Teams client to an SfB user

No Screen sharing in INTEROP

• Sfb user initiates screen sharing with a Teams user.
  • Then Teams uses clicks on the link and takes them to an SfB client
• Teams user initiates screen sharing to an SfB – doesn’t work.

Federation

• Will default to SfB unless you are in Teams only mode
• Islands mode or other Skype mode – federation received
• All federation occurs over the SfB gateway
• 10 minutes go by, it times out and the chat may go to the SfB client?
• Teams only state – Looking at native Teams federation

Data Migration

Contacts

Contacts are copied from Skype for Business Online in 2 phases.

• After the first logon to Teams, contacts are copied to Teams.
• At next Teams logon after Teams-only contacts are copied into Teams and merged with existing contacts

Implications for a user homed in Skype for Business on-prem:

• Contacts are moved to Skype for Business Online: Meetings are not migrated
• No Skype for Business contacts available in Teams until the user is Teams-Only.

Meetings

• If upgrading from Skype for Business Online, meetings are not required.
• If upgrading from Skype for Business On-prem, Meetings *are* migrated

• Groups
  • DLs are not supported in the contact view in teams
• Teams only mode – meetings are migrated to Teams
• Org-wide Teams only mode
  • Not automatically migrated to Teams
  • Would need to initiate a cmdlet to migrate the meetings

The following table compares the coexistence and upgrade modes.

Mode	Situation	Recommended Use	Advantages	Caveats
Islands	Smaller or simpler Skype for Business deployment Ability and willingness to manage some short-term complexity to move to Teams more quickly	Go to the full Teams experience as quickly as possible Conduct a proof of concept (PoC) of Teams Recommended upgrade path for organizations who adopted Skype for Business Online	Simple to operate Richest Teams experience up-front for all capabilities	Requires good user communication to avoid confusion and to drive usage toward Teams Exit strategy requires users to have fully adopted Teams prior to starting the upgrade to Teams Only phase No interop for users in Islands mode; also no federation from Teams when the user’s Skype for Business account is homed on-premises
Skype for Business with Teams collaboration	Skype for Business deployment with requirements that aren’t yet met by Teams (for example, advanced compliance) The long-term need for and/or commitment to Skype for Business	Start Teams adoption quickly, focusing on group collaboration first Want to keep all unified communications workloads on Skype for Business for now Recommended use as the starting point for an organization starting their journey from on-premises (or hybrid) Skype for Business	No overlapping capabilities between Teams and Skype for Business Instant messaging chat and meeting schedule will reside in Skype for Business (tied to calling) Interoperability with users in Teams Only
Skype for Business with Teams collaboration and meetings	Skype for Business deployment with significant use of enterprise voice and requirements that aren’t yet met by Teams calling The long-term need for and/or commitment to Skype for Business Might be using a third-party meeting service	Start Teams adoption quickly, going beyond group collaboration Improve your users’ meetings experience Recommended use for on-premises organizations wanting to take advantage of Teams meetings prior to being ready to fully upgrade (generally due to Enterprise Voice on-premises).	No overlapping capabilities Superior meetings on Teams. Features roadmap, UX and cross platform, quality and reliability “Better Together” experiences between Skype for Business and Teams Interoperability users in Teams Only.	Instant messaging and chat will reside in Skype for Business (tied to call)
Teams Only	Some users need to stay on Skype for Business You’re upgrading your Skype for Business Online users to Teams while keeping Skype for Business on-premises users on Skype for Business Server You might have already deployed users in islands mode and are ready to retire Skype for Business for groups of users	Reduce variable costs on Skype for Business (on-premises server operations, outsourcing contract, and so on) Go to the full Teams experience as quickly as possible, for at least some users	Limits user confusion by providing only one client to work with Interoperability with users in Skype for Business Only, Skype for Business with Teams Collaboration, Skype for Business with Teams Collaboration and Meetings	Interoperability only supports basic chat and calling between Skype for Business and Teams, and interop escalation scenarios for desktop sharing and multi-party chat and calling
Skype for Business only	Some users need to stay on Skype for Business	Limits user confusion by providing only one client to work with User can still participate in Teams meetings they are invited to	Continue to meet business requirements that currently can only be met by Skype for Business Interoperability with users in Teams Only	Interoperability only supports basic chat and calling between Skype for Business and Teams, and interop escalation scenarios for desktop sharing and multi-party chat and calling

Upgrade Journeys

You can take multiple approaches to upgrade from Skype for Business, either online or on-premises, to Teams:

• In a direct upgrade journey, you first deploy Teams alongside Skype for Business in Islands mode as part of the evaluation and early adoption and then upgrade your users to Teams Only mode with the goal of quickly retiring Skype for Business from the environment for all users in the organization.
• This is the recommended journey for Skype Business online customers unless they are concerned their users will be confused with having two tools to conduct the same action (chat, calling, meeting scheduling).
• A gradual upgrade journey delivers a specific coexistence and upgrade mode to a specific group of users (also called a cohort), depending on their communications and collaboration requirements. Over time, the entire organization can converge into using Teams Only and eventually replace Skype for Business.
• However, if your organization has compelling business reasons to keep Skype for Business—such as a dependency on a Unified Communications Managed API (UCMA)–based solution that integrates with line-of-business applications, or an ethical wall solution currently available for Skype for Business only, or a complex Enterprise Voice deployment that will take time to upgrade to Teams Only—you can upgrade a portion of users to Teams Only mode while retaining Skype for Business users in one of the coexistence modes for a portion of your user population.
• Gradual upgrade journey is the recommended approach for on-premises (and hybrid) customers starting with Skype for Business with Teams Collaboration coexistence mode and moving from there to Teams Only mode when the requirement for the users met (possibly through the Skype for Business with Teams Collaboration and Meetings coexistence mode).

Important

For both types of upgrade journey, if your organization is currently a Skype for Business on-premises deployment only, you need to start planning to implement Skype for Business hybrid before upgrading your users to Teams Only mode. This will also help facilitate interoperability with Teams.

Note:

• Teams Only mode requires that the users who are part of cohorts be homed in Skype for Business Online, and a hybrid relationship between your Skype for Business on-premises deployment and your Skype for Business Online tenant is required to facilitate the interoperability between Skype for Business and Teams. The move to Skype for Business Online must be completed for users who are part of the cohorts before they’ve upgraded to Teams Only mode.
• Skype for Business Server 2019 and Skype for Business Server 2015 with CU8 update can simplify the mechanics of upgrading on-premises users to Teams by managing the migration to Skype for Business Online and upgrading the users to Teams Only mode in one step.
• Direct upgrade journey – The direct upgrade journey is illustrated in the following diagram.

Teams is deployed to all users in the organization and configured in Islands mode. When your organization determines that Teams is ready to fulfill all of your communications and collaboration needs, notify the users and upgrade them to Teams Only mode. At that point, Skype for Business can be retired from the environment.

Gradual upgrade journey – An example of a gradual upgrade journey is illustrated in the following diagram.

Microsoft Teams and Skype for Business Comparison

For more information, visit the Microsoft website.

So that’s how I learnt coexistence mode teams.

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