Update release-notes/5.25.0.md

release-notes/5.25.0.md

@@ -81,6 +81,9 @@ Released May 6, 2020
   functions, but this first PR adds support for the aggregate functions `AVG`,
   `COUNT`, `MAX`, `MIN`, and `SUM`.
 
+- **install/index.php - Fix leak which breaks compatibility with current Backdrop
+  ([#17249](https://github.com/civicrm/civicrm-core/pull/17249))**
+
 ### CiviContribute
 
 - **Partial Refunds (Work towards