Document default blocksize for storbinary().
diff --git a/Doc/lib/libftplib.tex b/Doc/lib/libftplib.tex
index bb52f25..21fb8f5 100644
--- a/Doc/lib/libftplib.tex
+++ b/Doc/lib/libftplib.tex
@@ -173,12 +173,13 @@
default; in Python 2.1 and later, it is on by default.)
\end{methoddesc}
-\begin{methoddesc}{storbinary}{command, file, blocksize}
+\begin{methoddesc}{storbinary}{command, file\optional{, blocksize}}
Store a file in binary transfer mode. \var{command} should be an
appropriate \samp{STOR} command, i.e.\ \code{"STOR \var{filename}"}.
\var{file} is an open file object which is read until \EOF{} using its
\method{read()} method in blocks of size \var{blocksize} to provide the
-data to be stored.
+data to be stored. The \var{blocksize} argument defaults to 8192.
+\versionchanged[default for \var{blocksize} added]{2.1}
\end{methoddesc}
\begin{methoddesc}{storlines}{command, file}