开发团队已经于早些时候宣布了 PHP 5.2.1 可用的消息，据悉，本次发布主要是增强了 5.x 分支的稳定性和安全性。PHP 官方建议使用者升级到最新版。
在 PHP 5.2.1 发布公告中所列出的安全增强和修正有：
* Fixed a possible safe_mode & open_basedir bypasses inside the session extension.
* Prevent search engine from indexing the phpinfo() page.
* Fixed a number of input processing bugs inside the filter extension.
* Fixed unserialize() abuse on 64 bit systems with certain input strings.
* Fixed possible overflows and stack corruptions in the session extension.
* Fixed an underflow inside the internal sapi_header_op() function.
* Fixed allocation bugs caused by attempts to allocate negative values in some code paths.
* Fixed possible stack overflows inside zip, imap & sqlite extensions.
* Fixed several possible buffer overflows inside the stream filters.
* Fixed non-validated resource destruction inside the shmop extension.
* Fixed a possible overflow in the str_replace() function.
* Fixed possible clobbering of super-globals in several code paths.
* Fixed a possible information disclosure inside the wddx extension.
* Fixed a possible string format vulnerability in *print() functions on 64 bit systems.
* Fixed a possible buffer overflow inside mail() and ibase_{delete,add,modify}_user() functions.
* Fixed a string format vulnerability inside the odbc_result_all() function.
* Memory limit is now enabled by default.
* Added internal heap protection.
* Extended filter extension support for $_SERVER IN cgi AND apache2 SAPIs.
你可以从下面的链接下载到 PHP 的最新版，其中包括完整的源码包和用于 Windows 平台的二进制包。
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