diff --git a/appendices/migration84/incompatible.xml b/appendices/migration84/incompatible.xml
index 947b9dd167f5..f1251351dc94 100644
--- a/appendices/migration84/incompatible.xml
+++ b/appendices/migration84/incompatible.xml
@@ -517,19 +517,19 @@
   <title>MBString</title>
 
   <simpara>
-   On invalid strings (those with encoding errors),
-   <function>mb_substr</function> now interprets character indices in the same
-   manner as most other mbstring functions.
+   As of PHP 8.3.2, on invalid strings (those with encoding errors),
+   <function>mb_substr</function> and <function>mb_strstr</function> interpret
+   character indices in the same manner as most other mbstring functions.
    This means that character indices returned by <function>mb_strpos</function>
    can be passed to <function>mb_substr</function>.
   </simpara>
 
   <simpara>
-   For SJIS-Mac (MacJapanese) strings, character indices passed to
-   <function>mb_substr</function> now refer to the indices of the Unicode
-   codepoints which are produced when the string is converted to Unicode.
-   This is significant because around 40 SJIS-Mac characters convert to a
-   sequence of multiple Unicode codepoints.
+   For <literal>SJIS-mac</literal> (MacJapanese) strings, those character
+   indices refer to the indices of the Unicode codepoints which are produced
+   when the string is converted to Unicode, which differ from the character
+   indices for the <literal>SJIS-mac</literal> characters that convert to a
+   sequence of several codepoints.
   </simpara>
  </sect2>
 
diff --git a/reference/mbstring/book.xml b/reference/mbstring/book.xml
index 3de34d4edc8a..046c4e5031f8 100644
--- a/reference/mbstring/book.xml
+++ b/reference/mbstring/book.xml
@@ -28,14 +28,19 @@
    the multibyte character and ends up with a corrupted garbage string that
    most likely loses its original meaning.
   </para>
-  <para>
-   <literal>mbstring</literal> provides multibyte specific string functions 
-   that help you deal with multibyte encodings in PHP. In addition to that, 
-   <literal>mbstring</literal> handles character encoding conversion between 
-   the possible encoding pairs. <literal>mbstring</literal> is designed to 
-   handle Unicode-based encodings such as UTF-8 and UCS-2 and many 
+  <simpara>
+   <literal>mbstring</literal> provides multibyte specific string functions
+   that help you deal with multibyte encodings in PHP. In addition to that,
+   <literal>mbstring</literal> handles character encoding conversion between
+   the possible encoding pairs. <literal>mbstring</literal> is designed to
+   handle Unicode-based encodings such as UTF-8 and UCS-2 and many
    single-byte encodings for convenience (listed in <link linkend="mbstring.supported-encodings">Supported Character Encodings</link>).
-  </para>
+  </simpara>
+  <simpara>
+   The Unicode data tables used by <literal>mbstring</literal> have been
+   updated to Unicode 16.0 as of PHP 8.4.0, and to Unicode 17.0 as of
+   PHP 8.5.0.
+  </simpara>
  </preface>
  <!-- }}} -->
  
diff --git a/reference/mbstring/functions/mb-strstr.xml b/reference/mbstring/functions/mb-strstr.xml
index 96ec7d64252c..eb61d8e83ec2 100644
--- a/reference/mbstring/functions/mb-strstr.xml
+++ b/reference/mbstring/functions/mb-strstr.xml
@@ -84,6 +84,16 @@
      </row>
     </thead>
     <tbody>
+     <row>
+      <entry>8.3.2</entry>
+      <entry>
+       On invalid strings (those with encoding errors) and on
+       <literal>SJIS-mac</literal> (MacJapanese) strings, the portion of
+       <parameter>haystack</parameter> returned when
+       <parameter>before_needle</parameter> is &true; is now determined from
+       the same character indices as the other mbstring functions.
+      </entry>
+     </row>
      &mbstring.changelog.needle-empty;
      &mbstring.changelog.encoding-nullable;
     </tbody>
diff --git a/reference/mbstring/functions/mb-substr.xml b/reference/mbstring/functions/mb-substr.xml
index 7f769da05fdb..4fc252f73e6c 100644
--- a/reference/mbstring/functions/mb-substr.xml
+++ b/reference/mbstring/functions/mb-substr.xml
@@ -98,12 +98,17 @@
     </thead>
     <tbody>
      <row>
-      <entry>8.4.0</entry>
+      <entry>8.3.2</entry>
       <entry>
        On invalid strings (those with encoding errors),
        character indices are now interpreted in the same manner as most
        other mbstring functions. This means that character indices returned
        by <function>mb_strpos</function> can be passed directly.
+       For <literal>SJIS-mac</literal> (MacJapanese) strings, character
+       indices now refer to the indices of the Unicode codepoints produced
+       when the string is converted to Unicode, which differ from the
+       character indices for the <literal>SJIS-mac</literal> characters that
+       convert to a sequence of several codepoints.
       </entry>
      </row>
      &mbstring.changelog.encoding-nullable;
@@ -114,12 +119,10 @@
 
  <refsect1 role="seealso">
   &reftitle.seealso;
-  <para>
-   <simplelist>
-    <member><function>mb_strcut</function></member>
-    <member><function>mb_internal_encoding</function></member>
-   </simplelist>
-  </para>
+  <simplelist>
+   <member><function>mb_strcut</function></member>
+   <member><function>mb_internal_encoding</function></member>
+  </simplelist>
  </refsect1>
 
 </refentry>