July 2025 will bring massive challenges and fundamental changes to the Microsoft 365 ecosystem for IT administrators. From critical security vulnerabilities to recurring Exchange Online outages to the final end of the Classic Teams client. Here’s everything you need to know.
Massive Exchange Online disruptions mark July
July 2025 will go down in history as the month of Exchange outages. The disruptions reached a level that surprised even experienced IT administrators.
The big outage of July 10/11
On July 10, 2025, Exchange Online experienced the worst outage of the year – www.borncity.com:
- Duration: About 11 hours (Start: July 9, 22:20 UTC)
- Incident ID: EX1112414
- Affected regions: Global – USA, Europe, Australia, parts of Asia
- Symptoms:
- Complete loss of mailbox access
- Authentication Errors
- Error messages such as “Something went wrong” and “invalid licenses”
- Over 2,100 reports on DownDetector
The cause was a faulty configuration change that caused problems with the mailbox infrastructure and authentication components. Millions of users worldwide were affected, causing significant business disruption.
More July disruptions
The problems continued throughout the month:
- 1 July: 2 hours 11 minutes of disruption
- 2 July: 14 hour warning
- 6-7 July: Outages of several hours (up to 10h 53min)
- July 16 – ~21: Another massive disturbance (EX1112414 and EX1116357)
- Sending and receiving e-mails disrupted
- Delivery delays
- Outlook hung on “Trying to connect…”
- July 23rd: Error in the Exchange Online policies -> all mails got the addition in the subject: [EXTERNAL]
Impact on business operations
The repeated failures had significant consequences:
- Critical business communication was interrupted
- Customer documents were not accessible
- Project processes were delayed
- IT teams were working in crisis mode
Particularly problematic: The disruptions occurred more frequently, which made reliable planning impossible. Many organizations reported six-figure productivity losses.
Critical vulnerabilities and active threats
SharePoint on-premises under attack
The most urgent threat affects SharePoint On-Premises Server. Since July 7, 2025, several threat actors have been actively exploiting two critical vulnerabilities:
- CVE-2025-49706: A spoofing vulnerability
- CVE-2025-49704: A remote code execution vulnerability
Microsoft has confirmed that Chinese state actors (Linen Typhoon and Violet Typhoon) as well as the Storm-2603 group are exploiting these vulnerabilities. Storm-2603 distributes the Warlock ransomware. These attacks only affect on-premises installations – SharePoint Online is not affected.
Important: After installing the security updates, you must restart IIS. Without this step, the systems remain vulnerable. Microsoft has released comprehensive security updates for all supported SharePoint versions (Subscription Edition, 2019 and 2016).
Other safety measures
Starting in July 2025, Microsoft will enforce multi-factor authentication (MFA) for all users accessing the Microsoft 365 admin center. This measure is unavoidable in view of the increasing threat situation. Make sure all admins are prepared and have access to appropriate authenticator apps.
The end of Classic Teams: Hard deadline on July 1st
Microsoft is getting serious: The Classic Teams client has not been working since July 1, 2025. This concerns:
- Windows desktop versions
- macOS installations
- Virtual Desktop Infrastructure (VDI) Environments
- Windows 10 LTSC Systems
The situation is particularly problematic for organizations with older systems:
- Windows 10 versions prior to 19041 are not supported
- macOS versions older than Big Sur (11) are excluded
- Surface Hub v1 and Surface Hub 2S with Windows 10 Team Edition will lose Teams support
The only alternative is the web version under teams.microsoft.com. Urgently check if all workstations meet the system requirements for New Teams or if a browser-based solution needs to be implemented.
Fundamental changes to the update channels
Microsoft is fundamentally restructuring its update channels. These changes have far-reaching implications for your update strategy:
Monthly Enterprise Channel
- New: Rollback support will be extended from one to three months
- This provides more flexibility for problematic updates
- You can now revert to a stable version with the latest security updates for longer
Semi-Annual Enterprise Channel
- Support duration is drastically reduced from 14 to 8 months
- Microsoft now recommends this channel only for unattended devices
- Interactive seats should be migrated to Monthly Enterprise or Current Channel
- Feature releases will only be supported for 6 months (previously 14 months)
Semi-Annual Enterprise Channel (Preview)
- Will be fully retired from July 2025
- Affected systems must be migrated to Current Channel or Monthly Enterprise Channel immediately
Price increases for on-premises products
Microsoft is significantly increasing prices for on-premises products:
- All standalone on-premises servers (SharePoint, Exchange, Skype for Business): +10%
- Core CAL Suite: +15% (from August 1, 2025)
- Enterprise CAL Suite: +20% (from August 1, 2025)
These price changes only affect on-premises versions. The cloud variants (SharePoint Online, Exchange Online, Microsoft Teams) remain unchanged in price.
In addition, the Subscription Edition (SE) for Exchange Server and Skype for Business Server became generally available. This requires active Software Assurance or cloud subscription licenses for all users.
New Features and Developments
Microsoft 365 Copilot is expanding
AI integration is advancing with several important innovations:
- Image generation: Generally available in Microsoft 365 Apps from July 2025
- Voice Chat for iOS: Enables hands-free interaction with real-time interruption
- Security Copilot Integration: Automatic generation of KQL queries and incident analysis
- Audit and eDiscovery: New Compliance Features in Microsoft Purview for Copilot Actions
Teams Improvements
Despite initial migration problems, the new Teams client brings several advantages:
- Unified chat and channel interface
- Improved performance (up to 50% faster boot times)
- Enhanced Copilot integration for meeting summaries
- New message filtering and organization features
Other important changes
- Microsoft Lists Mobile Apps: Will be retired by November 2025
- Text Prediction in Outlook: Will be disabled by default from July 1
- New file type blocking: .library-ms and .search-ms are blocked in Outlook
July 2025 marks a turning point in Microsoft 365 development. The combination of forced migrations, critical security vulnerabilities and fundamental structural changes requires proactive action. While the short-term challenges are significant, the new features and structures offer long-term benefits for safety and productivity.
Prioritize your actions by criticality: security updates first, then migrations, followed by strategic adjustments. With a structured approach, the challenges can be overcome and the opportunities of modernization can be exploited.
