Status
Owner	Gautier Todeschini, Dawn Lai
Stakeholders	James Kyndt, Frank Bolata, Boris Foiselle

Decision: APRIL UPDATE: Option 1: Enable Teams Chat by wave, along with the migration of personal data

Previously Option 2: Enable Teams Chat for all employees from the start of the migration

Rationale: Option 2 would have created more concerning issue than the ones it tries to solve. Indeed, Teams is tighly linked to Calendar, and as non-migrated users will not have their Calendar on Microsoft, many notification processes would be disrupted (on top of the initially identified limitations detailed below)

Decision made by: Business Reps. (GBU/GBS/BSA)

Date: 25 Nov 2025

Online Meeting: Regular updates / Microsoft Transformation Program - GBU/GBS/BSA connection

Issue

Migrating users to M365 in a waved approach (4-5 waves over 3-5 weeks) will introduce a coexistence period between migrated users (having access to Teams and Google Chat if necessary) and non migrated users (having access to Google Chat only).

Recommendation

Option 2 - "Enable Teams Chat for all employees from the start of the migration" - early release with clear communication on the functional limitations of the Teams Client during Coexistence.

Options considered

A unified instant messaging platform from the start, or a clearer UX distinction between migrated & non-migrated users?
Option 1: Enable Teams Chat by wave, along with the migration of personal data.
Option 2: Enable Teams Chat for all employees from the start of the migration.

Evaluation

	Option 1: Enable Teams Chat by wave, along with the migration of personal data	Option 2: Enable Teams Chat for all employees from the start of the migration
Technical Feasibility	Slightly more simple as the enablement of Teams Chat will be setup in the migration sequence only (no need to plan a standalone service activation for the whole population at a given date)	Teams packages will have to be massively installed on employees' machines from the start which may result in more technical errors & necessary troubleshooting
User Impact	Reduced confusion around calendars and file storage: Users aren’t exposed to non-functional icons (Calendar, Files, OneDrive). Coexistence must be clearly communicated on especially the way to check if a user is migrated or not. Migrated users have to use two instant messaging platforms: Teams Chat with migrated users, Google Chat with others Users in different GBUs cannot chat or call across Microsoft Teams and must continue to rely on Google Chat for cross-BU communication. Risk of confusion or missed chat messages between migrated and non-migrated users.	All users (migrated or not) can chat and call immediately and stop using Google Chat. Simplifies rollout communications on impacts/coexistence Enables a single company-wide communication channel (Teams) Mixed UX for file sharing: migrated users can upload files directly in the Teams chat, non-migrated users can't (only share Google Drive URLs) Non-migrated users see tabs in Teams that won’t be functional until they migrate (ex: Calendar), which may create confusion (ex: unable to schedule meeting, Teams calendar not displaying coherent information with the actual agenda of the employee...).
End User Support	Migrated users get full Teams functionality (chat, calls, meetings, files, calendar), others stay entirely on Google until they are migrated. Support can focus on the migrated BU instead of the entire company.	Support desk must handle two populations of migrated users: Users with full functionality (migrated), Users with limited functionality (chat/call only). Potential tickets from non-migrated users "“Why can’t I upload from my desktop?” and "Why is my Calendar empty / not working"?
Operational Efficiency	Training and communications can be targeted and timed per BU.	Switches the “flow” of chats on the target platform immediately
Other	Teams’ adoption staggered — organization doesn’t reach the “network effect” of full collaboration until the last BU migrates.	Eases early adoption via early exposure to Teams for all users NB: Teams’ usage metrics will look inconsistent: many users enabled but only partially active until migration completes. Rebuild of SyRA Chat Agent to be defined
GBU/BSA/GBS Feedback	1/13 votes (November 25th, GBU connection call)	12/13 votes

Description	Repository

Issue

Recommendation

Options considered

Evaluation

See also