Greetings,
My take on this is that this is by upstream design. The manpage states
explicitly concerning IRC play:
"The version numbers of all participating programs must be equal."
I assume that you found some players using a different implemention of
XSkat that advertises itself as version 4.0, leading to this mismatch.
Quite possibly even the majority of IRC players use a different
implemention, given that there hasn't been a new upstream release of
this package here in 20 years now, and that the upstream homepage /
author seems to be missing.
With that in mind, I wouldn't like to arbitrarily change the program
version to make it compatible to certain other programs out there, of
which I don't even know which are popular and how compatible they
actually are.
However, I might be totally wrong on this, as I have just casually
glanced over the code now. And the above contains a log of assumptions
that might all be unfounded. If anyone has more insight into this,
that'd be greatly welcome. Marking this issue correspondingly.
Still, with upstream absent (cf. #1051639), and the code aging (cf.
#1075683), and me not using the package anymore (cf. #933098), the
general situation doesn't look all too rosy for XSkat ...
Cheers,
Flo