It's a messy, sad tale, so we'll give you the brief version: In 2001 there was an awesome game called Operation Flashpoint. After release, its developers and publisher split up, leaving the series in creative limbo.
Codemasters, the company publishing the game, retained the rights to it, and has gone on to release several new titles in the series.
Yet it was Bohemia Interactive who pioneered the idea and developed the first game. This is why they went off and made the ArmA series, which are basically Operation Flashpoint games without the name. Confusing for consumers, annoying for Bohemia.
That sad tale has a happy ending today, though, as the Czech developers revealed that the original 2001 game, Operation Flashpoint, has been "discontinued". In its place, they've regained the rights to release the game (if not use the Flashpoint name), and are bringing it back into the ArmA family where it belongs, renaming it Arma: Cold War Assault.
There's no major changes or updates or anything like that going on. They're just welcoming the prodigal son home!