On September 1 eigoMANGA released a sudden update for Vanguard Princess that adds quite a few features for the game.
The chief among them is online netplay with rollback netcode, but it also comes with a variety of compatibility updates and an easier option for configuring gamepad controls. The full list of changes can be found on the game's Steam page:
Online Versus — Challenge other players and fight online.
Offline Game — Play Vanguard Princess locally while remaining connected to the online lobby.
Online Lobby & Chat — Connect with other players, chat, issue challenges, and manage your availability.
Rest Mode & Seek Mode — Choose whether you're unavailable for challenges or let other players know you're looking for a match.
Game Settings — Adjust Stage, Rounds, Timer, Keyboard, and Controller settings directly through the new interface.
Expanded Controller Support — Improved support for modern gamepads and controllers.
Enhanced Game Presentation System — Integrated presentation of the original Vanguard Princess game through the updated interface.
Improved PC Compatibility — Additional support for modern Windows environments, display scaling, game startup, legacy Windows components, OneDrive installations, and other compatibility issues that can affect older PC games.
However, there is a big caveat here that this seems to be once again done without the involvement of original developer. Some time ago the publisher essentially claimed the title, while Suge9 is nowhere to be found.
If you care about Vanguard Princess and want to play it online, there is already a free option to do so thanks to netplay update for the engine Vanguard Princess was built on.

