Changelog for update GOG-9 (added 06.07.2015):

- We have uploaded a new Windows build of DEFCON that offers better offline functionality.

That's pretty vague. Could you be more specific please?

Is there any reason I need to update my copy of this game?

See here and conclusion.

Wow, that's quite a read. 18 pages for this issue to get fixed.

I haven't yet played this game so I'm not familiar with the issues people have been having but from what I can tell this new version does not phone home so there is no key issues and still has multiplayer?

If so, maybe the change-log could be amended to make that more clear.

Changelog for update GOG-13 (added 08.07.2015):

- We have uploaded a new Mac build of DEFCON that offers better offline functionality.

The single player launcher can't find prof.sb it gives back: sandbox-exec: profile not found. If this is because of OX x.6.8 then that's fine but it could just be the script.sh in the single player launcher. Not a huge problem, the key I have installed still works fine.

Changelog for update GOG-17 (Mac) (added 30 November 2016):

- The Mac version of DEFCON has received an updated version of the SDL framework and should be much more compatible with OS X 10.12.

Changelog for Update (added 27 November 2019):

- The Mac version of the game has been updated to work on macOS 10.15 Catalina


Standalone installer updated: (gog-17) ⇒ 1.0(64bit).