Provide version changed info
diff --git a/Doc/lib/libcmd.tex b/Doc/lib/libcmd.tex
index 4b2af91..4b7a23d 100644
--- a/Doc/lib/libcmd.tex
+++ b/Doc/lib/libcmd.tex
@@ -28,6 +28,7 @@
 instance will use for input and output. If not specified, they
 will default to \var{sys.stdin} and \var{sys.stdout}.
 
+\versionchanged[The \var{stdin} and \var{stdout} parameters were added.]{2.3}
 \end{classdesc}
 
 \subsection{Cmd Objects}