diff --git a/docs/en/04_Changelogs/4.0.0.md b/docs/en/04_Changelogs/4.0.0.md
index cbeb39e48..c280b6320 100644
--- a/docs/en/04_Changelogs/4.0.0.md
+++ b/docs/en/04_Changelogs/4.0.0.md
@@ -2071,6 +2071,8 @@ New `TimeField` methods replace `getConfig()` / `setConfig()`
 
 ### <a name="overview-testing"></a>SapphireTest
 
+* `is_running_tests()` is no logger public and user code should not rely on this. Test-specific behaviour
+  should be implemented in `setUp()` and `tearDown()`
 * `setUpOnce` removed. Please use `setUpBeforeClass`
 * `tearDownOnce` removed. Please use `tearDownAfterClass`
 * `TestListener` class removed