The new Debian Squeeze already release for some times. Today I have upgraded all my VPSes from Debian Lenny to Squeeze. Everything is working fine as expected.
Unfortunately, I found a problem when changing user password.
passwd ftpuser Current Kerberos password: passwd: User not known to the underlying authentication module passwd: password unchanged
OMG! This is a big problem for me as I'm having difference users/password for difference tasks. After Googling, found that this is caused by Kerberos! Just remove Kerberos and everything works as wish. Yeah!
apt-get remove libpam-krb5