docs: add changelog and upgrading guide

Author: kenjis

user_guide_src/source/changelogs/v4.4.0.rst

@@ -20,6 +20,15 @@ BREAKING
 Behavior Changes
 ================
 
+URI::setSegment() and Non-Existent Segment
+------------------------------------------
+
+An exception is now thrown when you set the last ``+2`` segment.
+In previous versions, an exception was thrown only if the last segment ``+3``
+or more was specified. See :ref:`upgrade-440-uri-setsegment`.
+
+The next segment (``+1``) of the current last segment can be set as before.
+
 Interface Changes
 =================
 

user_guide_src/source/installation/upgrade_440.rst

@@ -15,6 +15,19 @@ Please refer to the upgrade instructions corresponding to your installation meth
 Breaking Changes
 ****************
 
+.. _upgrade-440-uri-setsegment:
+
+URI::setSegment() Change
+========================
+
+Dut to a bug, in previous versions an exception was not thrown if the last segment
+``+2`` was specified. This bug has been fixed.
+
+If your code depends on this bug, fix the segment number.
+
+.. literalinclude:: upgrade_440/002.php
+   :lines: 2-
+
 Mandatory File Changes
 **********************
 

user_guide_src/source/installation/upgrade_440/002.php

@@ -0,0 +1,12 @@
+<?php
+
+// URI: http://example.com/one/two
+
+// Before:
+$uri->setSegment(4, 'three');
+// The URI will be http://example.com/one/two/three
+
+// After:
+$uri->setSegment(4, 'three'); // Will throw Exception
+$uri->setSegment(3, 'three');
+// The URI will be http://example.com/one/two/three