Key Dates

Upcoming Microsoft 365 rollout milestones, feature retirements, and compliance windows — organized by Modern Work practice area. Not everything here requires action; use the Applies to note to decide if it's relevant to your environment.

Last updated: 2026-09-08 · ← Back to homepage

Collaboration & Productivity

1 key date
Oct 1, 2026
Deadline
EWS Disablement in Exchange Online
Applies to Orgs with apps or service accounts still authenticating to Exchange Online via EWS
Audit all apps/service accounts still authenticating via EWS. Configure EWSAllowedAppIDs for stragglers and set internal migration milestones now - don't wait for enforcement to discover dependencies.

Security & Compliance

4 key dates
Oct 1, 2026
New Feature
Purview Endpoint DLP: Policy Sync & Device Health AI-Powered Investigation
Applies to Orgs running Purview Endpoint DLP across managed devices
No action required to adopt, but expect DLP policy sync failures to start surfacing root-cause explanations and recommended fixes automatically - worth a heads-up to whoever triages sync alerts today.
Oct 1, 2026
New Feature
Purview Endpoint DLP: Protect Sensitive Data over FTP/SFTP
Applies to Orgs with FTP/SFTP transfer paths from managed endpoints
If FTP/SFTP is a known exfiltration gap in your current DLP coverage, plan a policy pilot for this once it ships - it's new protocol coverage, not a change to existing policies.
Oct 1, 2026
New Feature
Microsoft Teams: Malicious URL Protection for Chat/Channels (Gov Clouds)
Applies to GCC, GCC High, and DoD Teams tenants
Confirm this closes a known protection gap for your Gov cloud tenant relative to commercial Teams, and update any compliance documentation that notes the discrepancy.
Jan 1, 2027
Deadline
Purview DLP: Restrict Copilot Processing of External Emails GA
Applies to Orgs with HIPAA/GDPR obligations around email data handled by Copilot
Begin policy design for restricting Copilot's processing of external emails ahead of the January 2027 GA, particularly if your organization handles regulated data via email.

Watching

Confirmed direction, no date yet — flagged for tracking, not the calendar
Watching · since Jul 2026
OWA Light Retirement in Exchange Server
Applies to Exchange Server (on-premises) customers with users still on OWA Light
Audit for users, browser policies, or helpdesk documentation pointing to the light client (`?layout=light`) and redirect them to standard Outlook on the web. Update internal training/help desk scripts now — no fallback exists once Microsoft disables it.
Microsoft has confirmed the retirement direction but has not published a specific date yet.