These features were deprecated at least 3 minor releases ago. I found
one mistake which was that `z_validateaddress` had not been placed
behind the `addrtype` deprecated feature; this has been fixed.
Since the wallet ecosystem may not be fully updated to handle
v5 transaction parsing at the point of NU5 activation, some
nodes may prefer to construct V4 transactions when not including
Orchard transaction components.
This change adds a CLI flag that allows node users to specify
that preference.