I've just updated my vpopmail to new 5.4.0. I always install every new version you release.
But from 25.4.0-preX" I have noticed authentication with cram-md5 passwords fails.
I hoped that installing the fresh stable 5.4.0 all this issue would leave apart, but it still continue.
- Update configure with correct location of vlimits.default.
- Fix typo (ammount) in vmoddomlimits. 
- Don't include $(DESTDIR) when building vpopmailbindir. 
- Mention compatability issues with older SMTP AUTH patches.
relevant portion of UPGRADE regarding SMTP AUTH (including CRAM-MD5):
IF USING SMTP AUTH PATCH TO QMAIL-SMTPD
* This release of vpopmail includes fixes for vchkpw that may break certain SMTP AUTH implementations. If SMTP AUTH fails after installing vpopmail 5.4.x, you may need to use the qmail-smtpd-auth-0.4.2 patch included in the contrib directory.
* If you do switch to the 0.4.2 SMTP AUTH patch, you may need to update
your qmail-smtpd run file (the first parameter to qmail-smtpd should
now be the path to vchkpw and not the hostname).
-- Tom Collins - [EMAIL PROTECTED] QmailAdmin: http://qmailadmin.sf.net/ Vpopmail: http://vpopmail.sf.net/ Info on the Sniffter handheld Network Tester: http://sniffter.com/