Warcraft 1 and 2 will leave GOG this December 13, exactly one month after Blizzard surprise-dropped its remasters of the games, but if you already own the games—or buy them before the 13th—you won't lose access. GOG is actually launching a discount code,
MakeWarcraftLiveForever, that you can use to knock $2 (£1.50) off the
Warcraft 1 and 2 bundle if you pick it up before D-Day (the D is for delisting).
There are a couple of wrinkles, though. One, Blizzard also sells the OG Warcrafts on Battle.net, and there's no word yet about whether they're also being delisted there. I've reached out to ask about that, and I'll update if I hear back. Even if Blizzard
does keep selling them, though, there are some differences between the Battle.net versions and GOG's. For instance, the GOG version of Warcraft 1 uses an internal config tool to make multiplayer connection a little easier, while GOG's Warcraft 2 comes with a new DXWrapper that tries to capture the game's original presentation on modern resolutions.