KLN 35A - needs an update

I need to remove my KLN 35A but I can't figure out how - small hole in the
front - I assumed it was for an allen wrench - none of mine fit it - too
small for a tiny screwdriver - what's the secret to getting this thing out ?
The battery in the unit is going dead and needs to be replaced - figured I
could do this myself if I could remove the unit.
Also going to have to update the database now that the battery died - and I
don't have a laptop to do an upgrade (couldn't get to the back of it anyway
if I did have one) - and I can't even seem to find a place to get an
update - the phone # in the manual is no longer good.
Any help here ?
Thanks,
Steve