docs: add changelog

user_guide_src/source/changelogs/v4.5.0.rst

@@ -21,6 +21,23 @@ BREAKING
 Behavior Changes
 ================
 
+Lowercase HTTP Method Name
+--------------------------
+
+For historical reasons, the framework used HTTP method names in lower case like
+"get", "post".
+But the method token is case-sensitive because it might be used as a gateway
+to object-based systems with case-sensitive method names. By convention,
+standardized methods are defined in all-uppercase US-ASCII letters.
+See https://www.rfc-editor.org/rfc/rfc9110#name-overview.
+
+Now the framework uses the correct HTTP method names like "GET", "POST".
+
+- ``Request::getMethod()`` returns uppercase HTTP methods.
+- ``CURLRequest::request()`` does not change the accepted HTTP methods to uppercase.
+
+See :ref:`upgrade-450-lowercase-http-method-name` for details.
+
 Filter Execution Order
 ----------------------