A community developer called 'Heat_XD' recently released a new fork of the popular PlayStation emulator Duckstation on GitHub that introduces GGPO rollback net code (as spotted by GamesRadar).
Without getting too much into the weeds about how net code in multiplayer games actually works (you can read this lengthy Ars Technica breakdown for a full explainer), that essentially now means that the PS1 emulator has a much smoother and better online experience than most modern fighting games, which typically launch without the highly-requested feature.
This new release will be especially welcome news for retro fighting game fans who want to play PS1 games competitively online but are worried about how internet connections may hinder their experience.
The latest version currently available is 0.1.75 (as of writing), and it's still actively being worked on. Therefore, Heat_XD warns players to still expect some "rough edges". From what we've seen so far, though, it already appears to be in a pretty good state.
Early feedback from members of the fighting game community also seems to be pretty positive, with experts like @maximilian_ and @GriffyBones being impressed with the results.
You can download it here.