The “ultimate and final version” of The King of Fighters ’98 first launched for PC via Steam on December 16, 2014, followed by Luna on March 3, 2022. It is also available via GOG and Humble Store.

On December 21, 2021, SNK and developer Code Mystics released a major update implementing rollback netcode, lobbies, and spectating modes.

Here is an overview of the game, via its Steam page:

About

After The King of Fighters ’98 often praised by the fans as the best installment in the The King of Fighters series, and The King of Fighters ’98 Ultimate Match 10 years later, The King of Fighters ’98 returns now on the Steam PC gaming platform in an ultimate and final version with The King of Fighters ’98 Ultimate Match Final Edition.

Key Features

• Super Smooth Fighting Online Awaits – In addition to implementing rollback netcode to make online fights even that much more smoother, The King of Fighters ’98 Ultimate Match Final Edition will now feature spectating modes and lobbies that can hold up to nine players! Smooth online fighting is just a click away!
• A Thorough Overhaul of the Game Balance – With an overall readjustment of the game balance and every character’s moves, this final edition of The King of Fighters ’98 Ultimate Match is definitely the ultimate version to play for every The King of Fighters fan for endless and epic battles.
• A Gorgeous Character Roster of 64 Fighters – In addition to the original roster of The King of Fighters ’98, emblematic The King of Fighters characters such as Eiji Kisaragi, Kasumi Todoh, Geese Howard, Mr. Big, and Wolfgang Krauser join this ultimate tournament. Furthermore, this final edition offers an alternate version to some characters for a total of 64 different fighters and infinite team possibilities.
• New System: Ultimate Mode – The newly added “Ultimate Mode” will allow you to combine the various features of the original “Extra” and “Advanced” game modes in order to create your own one! Moreover, classic “Extra” and “Advanced” two game modes have been thoroughly rebalanced for a wider variety of battle strategies.
• Two Different Online Features Available – Choose between “Rank Match,” where your battle results are reflected, and “Player Match,” where you can set your versus battle settings to your liking. Struggle to be the true King of Players in the limelight of the international stage! The world is yours!
• Original Neo Geo Version of The King of Fighters ’98 Included – The original Neo Geo version of The King of Fighters ’98 has been faithfully ported for the great pleasure of all! Discover or rediscover the quintessence of The King of Fighters on Steam!
• Various Game Modes – The King of Fighters ’98 Ultimate Match Final Edition features several game modes for the best game experience ever such as “Endless Mode,” in which you take on CPU-controlled characters in a series of battles, “Challenge Mode” to attempt and clear a total of 30 missions, and “Practice Mode,” where you can train using all types of moves and combos.