如果你安装某个web app,遇到提示：
We need PHP 5.3.6 or higher, you are running 5.3.3-7+squeeze17
解决办法：升级php
编辑/etc/apt/sources.list,添加如下四行：
deb http://packages.dotdeb.org squeeze all
deb-src http://packages.dotdeb.org squeeze all
deb http://packages.dotdeb.org squeeze-php54 all
deb-src http://packages.dotdeb.org squeeze-php54 all
wget http://www.dotdeb.org/dotdeb.gpg
apt-key add dotdeb.gpg
apt-get update
apt-get install php5 php5-gd php5-mysql php5-mcrypt
as3:~# php --version
PHP 5.4.22-1~dotdeb.0 (cli) (built: Nov 19 2013 06:35:18)
Copyright (c) 1997-2013 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2013 Zend Technologies
as3:~#
以上表明php成功升级到了5.4.22版。
参考：http://www.dotdeb.org/instructions/
