diff --git a/source/includes/mongodb-compatibility-table-php.rst b/source/includes/mongodb-compatibility-table-php.rst
index ae7fd69a..32985ed1 100644
--- a/source/includes/mongodb-compatibility-table-php.rst
+++ b/source/includes/mongodb-compatibility-table-php.rst
@@ -8,7 +8,7 @@
      - MongoDB 7.0
      - MongoDB 6.0
 
-   * - ext + lib 1.20 to 2.0
+   * - ext + lib 1.20 to 2.1
      - ✓
      - ✓
      - ✓
diff --git a/source/whats-new.txt b/source/whats-new.txt
index e7421ddd..f1fb23dd 100644
--- a/source/whats-new.txt
+++ b/source/whats-new.txt
@@ -33,6 +33,13 @@ following versions of the {+php-library+}:
 What's New in 2.1
 -----------------
 
+.. important:: Breaking Changes
+   The {+library-short+} v2.1 release introduces the following breaking
+   changes:
+
+   - Drops support for {+mdb-server+} 4.0. The minimum supported {+mdb-server+} version is
+     4.2.
+
 The {+library-short+} v2.1 release includes the following features,
 improvements, and fixes: