ID:778925
 
Resolved
Changing see_invisible or see_in_dark under certain conditions could confuse older clients (493 and earlier), even if the game did not use any new features that required a newer version.
BYOND Version:494
Operating System:Windows 7 Home Premium 64-bit
Web Browser:Firefox 12.0
Applies to:Dream Daemon
Status: Resolved (495)

This issue has been resolved.
I just updated my server to 494. Users who log in with pre-494 BYOND clients can't see the map - it's just a black screen. This issue is universal, and the only fix is for players to update to 494.

I would be nice to just give users a prompt saying that their DS is out of date, as has been done in the past.
+1

The prompt was a great feature back in the day, I don't know why it was removed seems silly.
Whoa, that's not good. 494 is supposed to be backwards compatible unless maptext is used, in which case it should prompt. As a temporary fix, you could compile some unused maptext code to force the prompt (and confirm that it works). We'll get in a proper fix for 495 asap.
Ah, that makes sense. Thankfully because the output pane still works, I was able to just give players an upgrade warning using client.byond_version and link them to the download page.
Lummox JR resolved issue with message:
Changing see_invisible or see_in_dark under certain conditions could confuse older clients (493 and earlier), even if the game did not use any new features that required a newer version.