... to the main game? Like for instance in Titan Quest?
Thanks!

Mostly, it depends on what you mean by improvements.

Stuff that affects the game mechanics (e.g. bug fixes, save anywhere feature) will work in the game as a whole no matter which campaign (Dead Man's Switch, Dragonfall and any user campaigns will get these changes).

There's also stuff that's Dragonfall specific, so you won't get Dragonfall-only spells/weapons/armour appearing in Dead Man's Switch.

The current change list is here: http://www.gog.com/forum/shadowrun_returns/shadowrun_returns_and_dragonfall_have_been_updated_to_version_126_pc_mac

It's split up into sections for the main game, DMS and DF, so that should let you know what's changed where. There's probably a historical change log somewhere (e.g. their website).

Thanks, that's exactly what I was relating to.