Yesterday I let cPanel do the 'emergency' upgrade that it wanted.

After the upgrade, Mail is no longer working.

When restarting exim, it says
exim status
3702 3698 2381 2377
exim started ok

Which is what it usually does.

But I can't check mail, as it's not responding to port 110.

Anyone know why it would do this?

either do:

service cpanel restart

or

/scripts/restartsrv cppop

Exim runs on port 25. Port 110 is pop3.

make sure that port 110 is open.

For that use the command
netstat -lpn|grep :110
check the output of above comand

check the error in the log if the exim is not starting.

tail -f /var/log/messages

From the log findout what the error is.

To solve most o the cpanel isu with exim..just execute the script
/scripts/exim4