服务器已安装Debian Wheezy OS。PHP版本是PHP5.3：
user@example:~# php -v
PHP 5.3.3-7+squeeze17 with Suhosin-Patch (cli) (built: Aug 23 2013 15:06:16)
我尝试通过APT-GET安装IMAP扩展名，结果是：
user@example:~# apt-get install php5-imap=5.3.3-7+squeeze17
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Version '5.3.3-7+squeeze17' for 'php5-imap' was not found
当我尝试另一个版本时，我会得到：
user@example:~# apt-get install php5-imap=5.3.3-7+squeeze19
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
php5-imap : Depends: php5-common (= 5.3.3-7+squeeze19) but 5.3.3-7+squeeze17 is to be installed
E: Unable to correct problems, you have held broken packages.
在这种情况下，有人知道安装PHP5-IMAP的最安全方法吗？P.S.从Wheezy Repo更新到5.4不是解决方案：（
我解决了使用imaplib（http://pymotw.com/2/imaplib/）的外部python脚本的问题。从PHP调用Python的示例：
<? exec("python <ABSOLUTE_PATH_TO_SCRIPT>.py " . escapeshellarg($arg1));