[Exim] Migrating from Exim 3.36 to Exim 4.10

Hello,

Our current mail hub is exim 3.36. I've setup a new mail hubb running exim
4.10 with sa-exim.

I'm not going to change our MX record I'm just going to replace the old
server with the new one.

But I'm hesitant to do so just because of the current queue on our old mail
hub. I dont want to lose any mail from being delivered to or from us.

Is it as simple as tarballing the /var/spool/mail from the old mail hub and
extracting it to the new mail hub?


Or is there a way to force delivery on all current mail in the queue but not
except any new mail?


Any ideas? Else I have to wait till the queue is very quite and then do the
swap.

TIA,
Ariel