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Microsoft Exchange Online auto-archiving rollout to prevent mail flow disruption

Service Disruption
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1 unique sources, 1 articles

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Microsoft is enabling threshold-based auto-archiving by default in Exchange Online to reduce mail flow disruption when mailboxes approach capacity. The feature moves the oldest mailbox items to archive storage as usage nears 90% of quota, helping prevent users from losing the ability to send or receive email. The rollout is underway this month for public clouds and is planned for November in government clouds.

Related Happenings

Microsoft Exchange CVE-2026-42897 mitigation advisory

Advisory/Mitigation
First: 15.05.2026 12:40 Last: 15.05.2026 12:40 Sources 1

About this happening: **Microsoft** issued immediate mitigation guidance for **CVE-2026-42897**, reducing risk for **Exchange Server 2016, 2019, and Subscription Edition (SE)** on-premises servers that...

Latest development: 15.05.2026 15:35

Microsoft issued temporary mitigation guidance for CVE-2026-42897 while a patch is still in development, recommending the Exchange Emergency Mitigation (EM) Service, which is enabled by default and can be checked with the Exchange Health Checker script, or the Exchange On-premises Mitigation Tool (EOMT) for disconnected or air-gapped environments. Microsoft noted that the mitigations can disrupt features such as OWA Print Calendar and Inline images, and that servers older than March 2023 cannot receive new mitigations through EM Service.

Open Happening

Microsoft Exchange Server spoofing/XSS flaw under active exploitation (CVE-2026-42897)

Vulnerability
First: 15.05.2026 09:19 Last: 15.05.2026 09:19 Sources 1

About this happening: **CVE-2026-42897** is an **actively exploited** **spoofing/XSS** flaw in **on-premises Microsoft Exchange Server** that can let attackers trigger **arbitrary JavaScript** in a bro...

Open Happening

Microsoft Exchange Online blocks legacy TLS for POP3 and IMAP4 starting July 2026

Security Tool/Service
First: 28.04.2026 16:18 Last: 28.04.2026 16:18 Sources 1

About this happening: **Microsoft** will block **TLS 1.0** and **TLS 1.1** for **POP3/IMAP4** access to **Exchange Online** in **July 2026**, which could break legacy mail clients and embedded devices...

Open Happening

Microsoft Outlook.com outage causing sign-in failures

Service Disruption
First: 27.04.2026 15:03 Last: 27.04.2026 15:03 Sources 1

About this happening: Microsoft's **Outlook.com** is experiencing an **ongoing outage** that is blocking sign-ins and mailbox access, leaving some customers unable to use email normally. The disruption...

Open Happening

NAKIVO Backup & Replication v11.2 general-availability release adds ransomware defense and secure email auth

Security Tool/Service
First: 18.04.2026 16:45 Last: 18.04.2026 16:45 Sources 1

About this happening: **NAKIVO Backup & Replication v11.2** is now generally available, adding **ransomware-resilience controls**, **OAuth 2.0 email authentication**, and expanded **VMware vSphere 9**...

Open Happening

Timeline

  1. 08.10.2025 20:49 2 articles · 7mo ago

    Exchange Online auto-archiving rollout

    Mitigation Patch Update

    Microsoft is rolling out threshold-based auto-archiving by default in Exchange Online so the Managed Folder Assistant can move the oldest items from primary mailboxes to archive mailboxes when usage approaches 90% of quota, reducing the risk of send and receive failures caused by full mailboxes. The change is rolling out this month for all public clouds and is scheduled to roll out for government clouds in November.

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