Thunderbrd
C2C War Dog
There is no obsolete function on improvements or builds besides being able to build the next up improvement and that only stops their availability if you have the "hide obsolete worker actions" BUG option turned on.
All I had time for was a quick check that all the XML pieces were there and linking correctly. I did not have time to do a test and wont until at least Wednesday.
Yeah, let me know how that goes. I'd been able to build factories on a modern start game so I was a little confused by this whole subject. Now that I'm understanding it, if we still have difficulties I'd be interested in taking a look but I'd need a savegame that displays the erroneous state.