# Updating packages in TeXLive 2011

I have TeXLive 2011 distribution on my Windows 7. I haven't updated it before. I downloaded it as an iso file. Anyway, I tried to use the mdframed package in an example document like below:

\documentclass{article}

\usepackage{mdframed}
\usepackage{xcolor}
\surroundwithmdframed[
hidealllines=true,
backgroundcolor=black!20,
skipbelow=\baselineskip,
skipabove=\baselineskip
]{equation}

\begin{document}
Text
$$1+1=2$$
Text
\end{document}

But I got the message:

! Undefined control sequence.

As I've asked it means possibly my mdframed package is not updated.
What should I do? I need to use the mdframed package.

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May be tex.stackexchange.com/a/55493/11232 is useful! – Harish Kumar Nov 27 '12 at 14:51
I have even tried this program but I don't think I need to update all the packages, do I? – Milad O. Nov 27 '12 at 14:56
I don't think so. May be it is possible to update only one package (I am not sure as I don't use texlive). But it is better to update every thing as an insurance policy :-) – Harish Kumar Nov 27 '12 at 15:04
Or you can just download the TeXLive 2012 iso if re-installation is an option – hpesoj626 Nov 27 '12 at 15:11