diff --git a/base/changes.txt b/base/changes.txt
index 78c788d9f..42dac8899 100644
--- a/base/changes.txt
+++ b/base/changes.txt
@@ -6,6 +6,10 @@ to completeness or accuracy and it contains some references to files that are
 not part of the distribution.
 ================================================================================
 
+2024-11-27  Yukai Chou  <muzimuzhi@gmail.com>
+	* clsguide.tex:
+	Add opt-arg to syntax of \Make...case
+
 2024-11-27  Joseph Wright  <Joseph.Wright@latex-project.org>
 	* usrguide.tex:
 	Add syntax of \Make...case
diff --git a/base/doc/clsguide.tex b/base/doc/clsguide.tex
index 1bc85999a..b52563564 100644
--- a/base/doc/clsguide.tex
+++ b/base/doc/clsguide.tex
@@ -42,7 +42,7 @@
     \texttt{clsguide.tex} for full details.}%
 }
 
-\date{2024-11-14}
+\date{2024-11-27}
 
 \NewDocumentCommand\cs{m}{\texttt{\textbackslash\detokenize{#1}}}
 \NewDocumentCommand\marg{m}{\arg{#1}}
@@ -1147,16 +1147,16 @@ \subsection{Case changing}
 \label{sec:case}
 
 \begin{decl}
-  |\MakeUppercase| \arg{text} \\
-  |\MakeLowercase| \arg{text} \\
-  |\MakeTitlecase| \arg{text}
+  |\MakeUppercase| \oarg{keyvals} \arg{text} \\
+  |\MakeLowercase| \oarg{keyvals} \arg{text} \\
+  |\MakeTitlecase| \oarg{keyvals} \arg{text}
 \end{decl}
 
 As described in \texttt{usrguide}, case changing for text should be carried out
 using the commands |\MakeUppercase|, |\MakeLowercase| and
 |\MakeTitlecase|. If you need to change the case of programmatic material, the
 team strongly suggest using the L3 programming layer commands in the
-\texttt{str} module. If you do not wish to do this, you should use the \TeX{}
+\texttt{l3str} module. If you do not wish to do this, you should use the \TeX{}
 |\uppercase| and |\lowercase| primitives \emph{in this situation only}.
 
 \subsection{Better user-defined math display environments}