Hey, everybody, Niko Bellic is heading back into town. Yep, Rockstar has announced that Grand Theft Auto 4 will return to Steam on March 19, 2020, but it will be missing multiplayer and online leaderboards. Both are casualties of Microsoft no longer supporting Games for Windows Live (opens in new tab) (aka the devil), which is what GTA 4 used to provide those services on PC previously.
That's not all that's missing, either, as the radio stations RamJam FM, Self-Actualization FM, and Vice City FM will be temporarily unavailable. A real shame as Vice City FM had some proper '80s pop bangers—"Maneater" by Hall & Oates will be sorely missed. Hopefully those stations are back soon.
If you already own GTA 4 then you'll be able to download an update to keep playing from March 19. It's a necessary download as GTA 4 and its DLC, Episodes from Liberty City, are being replaced with GTA 4: Complete Edition going forward. It just puts the base game and DLC into a single package. Any existing save files you have should transfer to the new version without a hitch. Fingers crossed.
Getting the download should be easy enough if you have the game on Steam or through the Rockstar Games Launcher. However, if you own a physical copy it's a little more complex. "Games previously activated using Games for Windows Live will require players to create and/or link their Social Club accounts in replacement of Games for Windows Live to update to Grand Theft Auto IV: Complete Edition," Rockstar writes on the Steam page. I don't envy anyone having to do that.
If you haven't activated GTA 4 through Games for Windows Live then you'll just need to activate the key on the back of the manual to get the new update. Though you should probably wait until March 19 when the Complete Edition becomes available, as Rockstar says your download may be disrupted otherwise.