[mono-packagers] Corlib not in sync with this runtime: expected corlib version 69, found 82

[Marc Weber]

I'm keen on part of an application which is written in C#.
That's why I tried updating the Nix distribution of Mono today.

%monodevelop
Corlib not in sync with this runtime: expected corlib version 69, found 82.
Loaded from: /nix/store/lv0k02i05mwpm44m1ywrp7n5ksvdnscm-mono-2.4.2.1/lib/mono/2.0/mscorlib.dll
Download a newer corlib or a newer runtime at http://www.go-mono.com/daily.

I've successfully build and installed these versions:
  monodevelop-2.2
  gtk-sharp-2.12.9
  gtkmozembed-sharp-0.7-pre41601
  mono-2.4.2.1

Now I'm lost. Can you tell me what exactly is going wrong here? Don't those versions fit?
Can you point me to the documentation telling me how to resolve this start issue?

Marc Weber