diff --git a/doc/system/changes.adoc b/doc/system/changes.adoc
index 1e49d32..6e51311 100644
--- a/doc/system/changes.adoc
+++ b/doc/system/changes.adoc
@@ -8,9 +8,13 @@ http://www.boost.org/LICENSE_1_0.txt
 ////
 
 [#changes]
-# Release History
+# Revision History
 :idprefix:
 
+## Changes in Boost 1.74
+
+* `operator bool()` now returns `failed()` instead of `value() != 0`.
+
 ## Changes in Boost 1.69
 
 * Boost.System is now header-only. A stub library is still built for