PHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML. If you are new to PHP and want to get some idea of how it works, try the introductory tutorial. After that, check out the online manual, and the example archive sites and some of the other resources available in the links section.
PHP Version 5.2.5 (08-November-2007)
* Security Fixes
o Fixed dl() to only accept filenames. reported by Laurent Gaffie.
o Fixed dl() to limit argument size to MAXPATHLEN (CVE-2007-4887).
o Fixed htmlentities/htmlspecialchars not to accept partial multibyte sequences.
o Fixed possible triggering of buffer overflows inside glibc implementations of the fnmatch(), setlocale() and glob() functions. Reported by Laurent Gaffie.
o Fixed "mail.force_extra_parameters" php.ini directive not to be modifiable in .htaccess due to the security implications reported by SecurityReason.
o Fixed bug #42869 (automatic session id insertion adds sessions id to non-local forms).
o Fixed bug #41561 (Values set with php_admin_* in httpd.conf can be overwritten with ini_set()).
* Upgraded PCRE to version 7.3 (Nuno)
* Added optional parameter $provide_object to debug_backtrace(). (Sebastian)
* Added alpha support for imagefilter() IMG_FILTER_COLORIZE. (Pierre)
* Added ability to control memory consumption between request using ZEND_MM_COMPACT environment variable. (Dmitry)
* Improved speed of array_intersect_key(), array_intersect_assoc(), array_uintersect_assoc(), array_diff_key(), array_diff_assoc() and array_udiff_assoc(). (Dmitry)
* Fixed move_uploaded_file() to always set file permissions of resulting file according to UMASK. (Andrew Sitnikov)
* Fixed possible crash in ext/soap because of uninitialized value. (Zdash Urf)
* Fixed regression in glob() when enforcing safe_mode/open_basedir checks on paths containing '*'. (Ilia)
* Fixed PDO crash when driver returns empty LOB stream. (Stas)
* Fixed iconv_*() functions to limit argument sizes as workaround to libc bug (CVE-2007-4783, CVE-2007-4840 by Laurent Gaffie). (Christian Hoffmann, Stas)
* Fixed missing brackets leading to build warning and error in the log. Win32 code. (Andrey)
* Fixed leaks with multiple connects on one mysqli object. (Andrey)
* Fixed endianness detection on MacOS when building universal binary. (Uwe Schindler, Christian Speich, Tony)
* Fixed imagerectangle regression with 1x1 rectangle (libgd #106). (Pierre)
* Fixed bug #43196 (array_intersect_assoc() crashes with non-array input). (Jani)
* Fixed bug #43139 (PDO ignores ATTR_DEFAULT_FETCH_MODE in some cases with fetchAll()). (Ilia)
* Fixed bug #43137 (rmdir() and rename() do not clear statcache). (Jani)
* Fixed bug #43130 (Bound parameters cannot have - in their name). (Ilia)
* Fixed bug #43099 (XMLWriter::endElement() does not check # of params). (Ilia)
* Fixed bug #43020 (Warning message is missing with shuffle() and more than one argument). (Scott)
* Fixed bug #42976 (Crash when constructor for newInstance() or newInstanceArgs() fails) (Ilia)
* Fixed bug #42943 (ext/mssql: Move *timeout initialization from RINIT to connect time). (Ilia)
* Fixed bug #42917 (PDO::FETCH_KEY_PAIR doesn't work with setFetchMode). (Ilia)
* Fixed bug #42890 (Constant "LIST" defined by mysqlclient and c-client). (Andrey)
* Fixed bug #42818 ($foo = clone(array()); leaks memory). (Dmitry)
* Fixed bug #42817 (clone() on a non-object does not result in a fatal error). (Ilia)
* Fixed bug #42785 (json_encode() formats doubles according to locale rather then following standard syntax). (Ilia)
* Fixed bug #42783 (pg_insert() does not accept an empty list for insertion). (Ilia)
* Fixed bug #42773 (WSDL error causes HTTP 500 Response). (Dmitry)
* Fixed bug #42772 (Storing $this in a static var fails while handling a cast to string). (Dmitry)
* Fixed bug #42767 (highlight_string() truncates trailing comment). (Ilia)
* Fixed bug #42739 (mkdir() doesn't like a trailing slash when safe_mode is enabled). (Ilia)
* Fixed bug #42703 (Exception raised in an iterator::current() causes segfault in FilterIterator) (Marcus)
* Fixed bug #42699 (PHP_SELF duplicates path). (Dmitry)
* Fixed bug #42654 (RecursiveIteratorIterator modifies only part of leaves) (Marcus)
* Fixed bug #42643 (CLI segfaults if using ATTR_PERSISTENT). (Ilia)
* Fixed bug #42637 (SoapFault : Only http and https are allowed). (Bill Moran)
* Fixed bug #42629 (Dynamically loaded PHP extensions need symbols exported on MacOSX). (jdolecek at NetBSD dot org)
* Fixed bug #42627 (bz2 extension fails to build with -fno-common). (dolecek at netbsd dot org)
* Fixed bug #42596 (session.save_path MODE option does not work). (Ilia)
* Fixed bug #42590 (Make the engine recognize \v and \f escape sequences). (Ilia)
* Fixed bug #42587 (behavior change regarding symlinked .php files). (Dmitry)
* Fixed bug #42579 (apache_reset_timeout() does not exist). (Jani)
* Fixed bug #42549 (ext/mysql failed to compile with libmysql 3.23). (Scott)
* Fixed bug #42523 (PHP_SELF duplicates path). (Dmitry)
* Fixed bug #42512 (ip2long('255.255.255.255') should return 4294967295 on 64-bit PHP). (Derick)
* Fixed bug #42506 (php_pgsql_convert() timezone parse bug) (nonunnet at gmail dot com, Ilia)
* Fixed bug #42462 (Segmentation when trying to set an attribute in a DOMElement). (Rob)
* Fixed bug #42453 (CGI SAPI does not shut down cleanly with -i/-m/-v cmdline options). (Dmitry)
* Fixed bug #42452 (PDO classes do not expose Reflection API information). (Hannes)
* Fixed bug #42468 (Write lock on file_get_contents fails when using a compression stream). (Ilia)
* Fixed bug #42488 (SoapServer reports an encoding error and the error itself breaks). (Dmitry)
* Fixed bug #42378 (mysqli_stmt_bind_result memory exhaustion). (Andrey)
* Fixed bug #42359 (xsd:list type not parsed). (Dmitry)
* Fixed bug #42326 (SoapServer crash). (Dmitry)
* Fixed bug #42214 (SoapServer sends clients internal PHP errors). (Dmitry)
* Fixed bug #42189 (xmlrpc_set_type() crashes php on invalid datetime values). (Ilia)
* Fixed bug #42139 (XMLReader option constants are broken using XML()). (Rob)
* Fixed bug #42086 (SoapServer return Procedure '' not present for WSIBasic compliant wsdl). (Dmitry)
* Fixed bug #41822 (Relative includes broken when getcwd() fails). (Ab5602, Jani)
* Fixed bug #39651 (proc_open() append mode doesn't work on windows). (Nuno)
更新：http://php.net/ChangeLog-5.php
官网：http://www.php.net/
PHP是一种新型的CGI程序编写语言，易学易用，运行速度快，可以方便快捷地编写出功能强大，运行速度快，并可同时运行于 Windows、Unix、Linux平台的Web后台程序，内置了对文件上传、密码认证、Cookies操作、邮件收发、动态GIF生成等功能，PHP直接为很多数据库提供原本的连接，包括Oracle、Sybase、Postgres、Mysql、Informix、Dbase、Solid、Access等，完全支持ODBC接口，用户更换平台时，无需变换PHP代码，可即拿即用。
Download: PHP 5.2.5 for Windows2000/XP
Download: PHP 5.2.5 for Linux