This weekend, I'm in the process of upgrading my Cyrus server from 4.x to 6.x, and thought I'd send out a few notes from places I gently stubbed my toe: (0) When you boot the 4.x user space on a 5.x kernel, you will get a lot of warnings about sysctls and mount. These can be safely ignored during the upgrade. (1) If you use an mfs file system, such as /tmp, in 4.x, remember to remove that entry from /etc/fstab before booting a 5.x user space. I replaced my mfs entry in fstab with: tmpmfs="YES" tmpsize="512M" (2) Several make.conf entries have changed. I no longer need MAKE_KERBEROS5, since it's now the default, but I had to change my NOROFILE entry to NO_PROFILE. I now no longer need my NOUUCP entry. (3) Remember to rm -Rf /usr/obj before each build phase, or you can trip over leavings. For example, I can't compile a 6.x world on a 5.x user space with 4.x and 5.x leavings in /usr/obj. (4) I use postfix, not sendmail, and had to add the following line to my /etc/rc.conf so that my 4.x postfix build could be properly stopped and restarted using /etc/rc.d/sendmail: sendmail_procname="/usr/local/libexec/postfix/master" Likewise, I'm probably missing some entries in /etc/mail/mailer.conf; there are two new ones since 4.x. rc.d is still getting upset because the aliases.db isn't getting rebuild as a result of running newaliases, and warning about it each start/stop event. (5) Speaking of which, if you want to run 4.x binaries, remember to build a kernel with COMPAT_FREEBSD4 :-). Right now I don't have compat4x packages installed, since I've left the old libraries in place, but should either do that or update the packages installed. (6) At some point, megemaster created an /etc/pam.d on 4.x, possibly user error on my part, and having an empty pam.d directory turns out to really upset PAM, which can't find any config files there, but won't use pam.conf because the directory is there. A serial console is a good thing(tm). (7) Switching to a custom kernel configuration file based in "include" is a very good thing. Robert N M Watson