Exchange Online
The latest Exchange Online coverage — news, analysis, and updates from the WindowsNews.AI desk.
Per-Mailbox Cloud Management Lets Admins Finally Retire the Last Exchange Server
Microsoft has released a per‑mailbox cloud management feature that finally gives hybrid Exchange organizations a clear path to unplugging the last on‑premises Exchange server. With the new...
Microsoft Caps onmicrosoft.com Emails at 100 External Recipients Per Day — Enforcement Starts October 15
Microsoft will begin throttling emails sent from the default onmicrosoft.com domain to just 100 external recipients per day, starting with trial tenants on October 15, 2025. The limit is a hard cap...
Microsoft Reverses Exchange Online Boost That Quarantined Outlook Mobile Sync for 12 Hours
Microsoft is rolling back a recent Exchange Online update after a performance optimization inadvertently caused 12‑hour mail sync delays for Outlook mobile users in hybrid environments. The...
Microsoft to Slash onmicrosoft.com Outbound Email to 100 External Recipients per Day — Staged Rollout Begins October 2025
Microsoft will soon enforce a hard limit on external email sent from the shared onmicrosoft.com namespace, capping it at just 100 external recipients per tenant per day. The policy, dubbed MOERA...
Microsoft Slashes onmicrosoft.com Outbound Email to 100 Recipients Daily to Fight Spam
Starting October 15, 2025, Microsoft will begin enforcing a hard cap of 100 external email recipients per 24 hours for all tenants sending from the default onmicrosoft.com domain. The move, announced...
Microsoft’s August 2025 Hotfixes Force Skype for Business Hybrid Users to Switch Dedicated Apps by October 15
Microsoft dropped an August 2025 hotfix bomb for Skype for Business Server that kills the comfort of a shared service principal and replaces it with a tenant-owned Dedicated Hybrid Application....
CISA Mandates Immediate Disconnect of EOL Exchange Servers After Black Hat Exploit Demo for CVE-2025-53786
A critical Microsoft Exchange Server vulnerability now carries a binding directive from the U.S. Cybersecurity and Infrastructure Security Agency, following a live demonstration of the exploit at the...
CVE-2025-53786: How a Hybrid Exchange Flaw Turns On-Prem Access into Cloud Catastrophe
Attackers who manage to breach an on-premises Microsoft Exchange server can now pivot to the cloud with a set of unrevocable credentials—and for 24 hours, defenders are all but helpless. That is...
CVE-2025-53786: The Silent Hybrid Exchange Exploit That Bypasses All Cloud Defenses
Microsoft has issued an urgent warning about a high-severity vulnerability in hybrid Exchange deployments that could let attackers who breach an on-premises server silently escalate their privileges...
CISA Emergency Directive Targets CVE-2025-53786: Hybrid Exchange Flaw Demands Immediate Action
The Cybersecurity and Infrastructure Security Agency (CISA) issued Emergency Directive 25-02 on August 7, 2025, compelling federal agencies to immediately patch a high-severity Microsoft Exchange...
Microsoft Ends Public Folder Migrations from Legacy Exchange Servers in 2025: A Crucial IT Modernization Milestone
Microsoft's decision to halt public folder migrations from legacy Exchange servers as of October 1, 2025, marks a defining moment for enterprise IT infrastructures deeply reliant on Exchange's...
Optimizing Internal Communications with Microsoft 365 Exchange Online High Volume Email
Modern enterprise environments thrive on the rapid, reliable dissemination of information. Whether this involves pushing automated IT alerts, distributing critical system notifications, or sending...