php 5.3.6 breaks my regex pattern

Question

Weird things happened when a website I am working on got moved to another server with newer version of PHP. The regex that was working normally on 3 other different servers refuses to work, returns 0 all the time.
This is the original regex:

/\A(?P<text>[[:alpha:]]{4})[[:space:]](?P<password>[\p{L}\p{N}]{3,})[[:space:]](?P<digit1>[[:digit:]]{2,4})[[:space:]](?P<digit2>[[:digit:]]{1,2})\z/u

password had to be unicode, before it was just [[:alnum:]] but there were some problems with clients.
And these are the ones I tried to no avail:

/\A(?<text>[[:alpha:]]{4}) (?<password>[[:alnum:]]{3,}) (?<digit1>[[:digit:]]{2,4}) (?<digit2>[[:digit:]]{1,2})\z/u
/\A(?<text>[\p{L}]{4}) (?<password>[\p{L}\p{N}]{3,}) (?<digit1>\d{2,4}) (?<digit2>\d{1,2})\z/u

Example text: ABCD 1a2b3c 100 50

All of these were tested on http://www.spaweditor.com/scripts/regex/index.php and worked perfectly.

Can anyone tell me what's wrong with it? I know it might not be the prettiest regex you've seen but it works (or at least worked until now) just like expected. Right now I'm blaming the PHP (lol).

Edit: tested the last pattern on these sites:
* http://regex.larsolavtorvik.com/
* http://www.spaweditor.com/scripts/regex/index.php
* http://www.pagecolumn.com/tool/pregtest.htm
* http://lumadis.be/regex/test_regex.php
and on some others where it allowed to type my regex fully myself, with slashes and u flag. In all of these websites it worked, but on some others I checked it didn't, same as my server.

PCRE is unicode-enabled...

Edit: seems that sysadmins changed something after all... didn't work until 10 minutes earlier :/ Somebody close this question, all of the regexes now work.

Answer 1

You should check your PCRE extension version (phpinfo() -> PCRE Library Version). Some servers have < 8, and version >= 8 only supports unicode.

Here is a good example on how to fix the problem on CentOS with PHP 5.2, you can check it with PHP 5.3 also.