Dwarf Fortress 0.43.03/0.43.04 are out now (the latter having some issues), and next versions will now be 64bit, which means it will possibly take long time until DFHack supports them.
Initially, I was planning to support last version in each DF release cycle, which would be 0.40.24, 0.42.06 and 0.43.04. However, now that 0.43 release cycle seems to be finished, there's no point in supporting 0.42. But also since saves from previous versions can be used with 0.43, there's almost no point in supporting 0.40, which would greatly simplify the development.
The only problem is that this will be a very bad surprise for users who update the app and can no longer connect to their server without additional actions, even if it's just a simple DF update. I'm thinking about releasing another app version now that would show a note about the upcoming update.
I'm still deciding what to do, in the meanwhile just continuing to implement 0.42/0.43 new features. By the time I finish, it should be clear what the last build in 0.43 cycle is, and how difficult it is for me to support several DF versions.