diff --git a/changelog.md b/changelog.md
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+++ b/changelog.md
@@ -13,6 +13,7 @@
 
 |When	|Duration | What	|
 | --- | --- | --- |
+| Jun 4 2026 | 16:30-17:15 PT 45min (unplanned) | `/sdf/home`, `/sdf/group`, `/sdf/sw` outage during routine firmware upgrades for one model of server - An issue with the vendor's firmware upgrade tooling briefly stopped cooling fans in each server during each upgrade. A small percentage of servers overheated during this time, impacting `sdfhome` storage. |
 | April 21st 2026 10:00-11:00 PDT | 1 hr (planned) | DTN nodes s3dfdtn.slac.stanford.edu, sdfdtn[001-006] will be rebooted during the maintenance window to apply security updates. This may interrupt currently-running transfers. Reboots will be done in batches to minimize disruption.
 | February 4th 2026 | 9:00-13:00 PST (planned) | Shutdown the Globus node  “sdfdtn004” for a network card upgrade.
 | March 18th 2026 11:00-12:00 PDT | 1 hr (planned) | DNS maintenance for s3dflogin s3dflogin-mfa s3dfdtn