I had the same issue but discovered screen 5.0.0 is not even able to read an empty screenrc, see this bug (https://savannah.gnu.org/bugs/?66158) I  submitted. Maybe that's the real issue?

This is more a request for help rather than reporting a bug (though this could be a bug).

I'm looking to update my screen install from 4.9.1 to 5.0.0. Unfortunately my
hardstatus doesn't work.

My 4.9.1 hardstatus is:

hardstatus string '%{gk}[%{G}%H%{g}][%= %{wk}%?%-Lw%?%{=b kR}(%{W}%n*%f %t%?(%u)%?%{=b kR})%{= kw}%?%+Lw%?%?%= %{g}]%{=b C}[%m/%d/%y %c]%{W}'

I converted the color specifications to the following for 5.0.0. See below:

hardstatus string '%{2;0}[%{i2}%H%{2}][%= %{7;0}%?%-Lw%?%{=b 0;i1}(%{i7}%n*%f %t%?(%u)%?%{=b 0;i1})%{= 0;7}%?%+Lw%?%?%= %{2}]%{=b i6}[%m/%d/%y %c]%{i7}'

The issue is that it just doesn't work. From what I can tell the %? conditions no longer work.

I'm not a screenrc hardstatus expert, novice actually in that department. Someone else had sent a copy of this to me for inclusion into the FreeBSD port. It worked great with screen 4. But there's something I'm missing even after converting the colors from the letter notation to the number notation. But I simply can't identify it.

Can someone please review this and help me?