imap4 search criteria

Hi, I noticed that the imap extension seems to support only IMAP2 search criteria. This is caused by the fact that in ext/imap/php_imap.c, the imap_search function uses a call to mail_criteria. And the University of Washington IMAP toolkit mentions in docs/internal.txt: SEARCHPGM *mail_criteria (char *criteria); criteria IMAP2-format search criteria string This function accepts an IMAP2-format search criteria string and parses it. If the parse is successful, it returns a search program suitable for use in mail_search_full(). WARNING: This function does not accept IMAP4 search criteria. Is there any specific reason why PHP uses this mail_criteria call ? It really would be nice to be able to use IMAP4 search criteria ! Thanks, Dominik