@Peter_B I suggest you save your notes but do not necessarily re-enter them (even by hand) afterward.
Many changes since that firmware was released, to what is normal now for an up-to-date network/router. 'Blindly' putting in old settings just because they worked so long ago doesn't make sense.
I suggest having a look at the M&M Config guide found in the link in my signature below and use those best practice 'defaults' to begin with. Add anything you need one feature at a time making sure you are testing at each step (including a reboot of the router and the clients too) to ensure all is working as you expect and need.