Overview
Microsoft has announced the end of extended support for Exchange Server 2016 and 2019 effective October 14, 2025, creating significant security implications for organizations still running these versions. This deadline affects technical support, security updates, and time zone patches.## Whom it may concern* IT Infrastructure Teams* Security Operations Teams* Email System Administrators* Compliance Officers## Key Findings1. No security patches after October 20252. No technical support for stability issues3. Migration options available to Exchange Online or Exchange Server SE4. In-place upgrade path available from Exchange 2019 to SE## Risk Analysis* High exposure risk due to unpatched vulnerabilities* Probability: High (100% certainty of support termination)* Impact: Critical (affects core email infrastructure)* Time to mitigate: 9 months until deadline## Action Items* Immediate audit of Exchange Server versions* Plan migration to Exchange Online or wait for Exchange Server SE* Complete transitions before October 14, 2025* Review Microsoft 365