在www.php.net上php4.0.6正式推出了--这个版本修正了4.0.5的很多Bug-同时对内存的利用更有效-如果您还在用4.0.4那么直接升级到4.0.6会更稳定。下面是4.0.6的主要改进：
Fixed memory fragmention problem which could lead to web server processes growing much more than they should. (Andi, Zend Engine)
Made $HTTP_SESSION_VARS[foo] and $foo be references to the same value when register_globals is on. (Andrei)
Fixed disk_free_space() and disk_total_space() under FreeBSD. (Jon)
Fixed readfile/passthru losing resources during connection abort (Sascha)
Fixed bug in the mcrypt extension that caused segfaults when using a key that is too large for the used algorithm, and a bug that caused mcrypt_generic() to segfault PHP (Derick)
Fixed getopt so that it accepts command line arguments in the form - and - . (Jmoore)
Fixed race in writing session files (Sascha)
Fixed a possible crash in the PHP CGI when no input file is specified (Zeev)
Added is_callable() function that can be used to find out whether its argument is a valid callable construct. (Andrei)
Fixed a rare possible crash when generating extended information. (Dmitri Dmitrienko, Zend Engine)
Improved virtual() to support PHP-enabled URIs. (Zeev)
Fixed undefined behavior when using floating point keys in array() expressions. (Zeev, Zend Engine)
Fixed a possible crash in case of parse errors in include files or eval statements. (Zeev, Zend Engine)
Added --with-layout configure option. (Stig)
Improved interactive mode - supports function calls, and works in multithreaded builds. (Zeev, Zend Engine)
Fixed a crash bug in interactive mode. (Zeev, Zend Engine)
Added pg_last_notice() function. (Rasmus from suggestion by [email protected])
Fixed a bug in preg_split() that would incorrectly limit the number of results when used along with PREG_SPLIT_NO_EMPTY flag. (Andrei)
Added connection error support to mysql_error() and mysql_errno(). (Jason)
Added support to getimagesize to return dimensions of BMP and PSD files. (Derick)
Added heuristic to kill stale IRC connections, message scanner caching, and nickname escaping to IRCG, suppress option to ircg_msg(), and statistics to IRCG phpinfo() output. (Sascha)
Added Japanese multibyte string functions support. (Rui)
Added Mac OS X "r" line ending support. (Andi, Zend Engine)
Fixed a bug regarding the $PHP_SELF being incorrectly registered when force-cgi-redirect was not enabled. (Sterling)
pfpro extension now supports version 3 of the Verisign SDK. (John Donagher)
Udm_Cat_List and Udm_Cat_Path functions has been added.
Added key_exists() to check if a given key or index exists in an array or object. (David Croft)
Modify the cURL extension to compile only with the latest cURL release. Backwards compatibility with regards to the extension api has not been broken. (Sterling)
Added the ability to use user-defined callbacks with cURL. (Sterling)
Added the SSL_VERIFYPEER, CAINFO, MAXREDIRS, FILETIME, RANDOM_FILE, EGDSOCKET and CONNECTTIMEOUT options to curl_setopt(). (Sterling)
Added support for persistent connections with cURL. (Sterling)
Fixed a problem in cURL with file descriptors being allocated, but never closed. (Sterling)
Fixed interactive mode (-a). It works again with the same limitations it has always had. (Andi, Zend Engine)
Improved memory manager to use less memory and provide better memory overflow detection abilities in debug mode. (Andi, Zend Engine)
Fixed resource leaks when resources were being cast to numbers. (Zeev, Zend Engine)
Fixed foreach() to not crash when being sent an invalid argument. (Andi, Zend Engine)
Fixed a bug in opendir() under Windows when trying to open a non-exisiting directory. (Andi)
Fixed popen() and the exec family under Win32 (Unable to fork issue). (Daniel)
Make the printf family of functions binary clean. (Rasmus)
Fixed WDDX serialization to HTML-escape key/variable names so as not to break the XML packet. (Andrei)
Made WDDX extension enabled by default. (Andrei)
Added -C command-line option to avoid chdir to the scripts directory. (Stig)
Fixed a bug with /e modifier in preg_replace(), that would not correctly replace two-digit references if single digit references were present before them. This fixed bug #10218. (Andrei)
Added temporary LOB support in OCI8. (Patch by David Benson)
Fixed crash in pathinfo()
OCI8 now supports binding of collections. (Patch by Andy Sautins )
Added GD 2.0.1 support for truecolor and alpha channels, plus some other gd functions, both old and new - see docs for more info. (Wez)
Added S/MIME sign/verify encrypt/decrypt functions to openssl extension, along with some other certificate manipulation and interrogation functions. See docs for more info. (Wez)
printf argnum (parameter swapping) support. (Morten Poulsen, Rasmus)
Add DIRECTORY_SEPARATOR constant (/ on UNIX, \ on Windows). (Stig)
Added small change to php_odbc module, to check for failed SQLDisconnects and to close any outstanding transactions if the call fails, then disconnect again. (lurcher)
Modified get_parent_class() and get_class_methods() to accept a class name as well as a class instance. (Andrei, Zend Engine)
Added support for UNC style paths. (\serversharefile, //server/share/file). (Daniel, TSRM)
Added dbx module (database abstraction) to the repository. (Marc)
Using ITypeInfo instead of IDispatch if possible. This makes DCOM calls and even COM calls much faster. All ini settings are now prefixed by com.. Now you need not provide a path to the file containing the typelib, you can also provide the GUID of the TypeLib - entry or an IID for preloading type - information. (phanto)
Rewrite of domxml. Its now mostly DOM Level 2 conform. (Uwe)
Added array_map() function that applies a callback to the elements of given arrays and returns the result. It can also be used with a null callback to transpose arrays. (Andrei)
Added array_filter(), which allows filtering of array elements via the specified callback. (Andrei)
Fixed all relevant array functions to avoid moving the internal array pointer during operations. (Andrei)
Added mysql_unbuffered_query(), which is useful for very large result sets. (Zeev)
摘自：LinuxByte