exim and cpanel upgrade now exim permission issues

Hello all. I have a server that was a bit behind the times and I've spent two days upgrading cpanel, apache/PHP, mysql, exim, etc. I don't recall what my cpanel/WHM version was previously, but it was just upgraded to the most recent - 11.84. During this process, I also updated exim to 4.92.3. My mail has worked for years up until this update, now I'm getting permission error such as the following:

• Failed to create directory "/var/spool/exim/db": Permission denied
• failed to open database lock file /var/spool/exim/db/retry.lockfile: Permission denied (euid=93 egid=93)

(uid/gid 93 is exim.exim) /var/spool/exim and all directories below it are 750 mailnull.mail drwxr-x--- 6 mailnull mail 4.0K Dec 28 16:16 exim drwxr-x--- 2 mailnull mail 4.0K Sep 30 11:51 db drwxr-x--- 32 mailnull mail 4.0K Dec 28 20:45 input drwxr-x--- 32 mailnull mail 4.0K Dec 28 15:08 msglog drwxr-x--- 2 mailnull mail 4.0K Dec 27 01:44 scan It looks like exim is running as the exim user instead of mailnull, which is causing it to be unable to use the spool directories. I tried changing them recursively to exim.exim and restarting the server, but that didn't help. I was hoping to find where I can change the exim runtime user to mailnull in /etc/exim.conf but can't find it. What am I missing?