An industry insider (RalphsValve) has heard that Rockstar is planning to remaster Grand Theft Auto 4. The game will be launched for all major platforms sometime in 2023. It will be single-player only and include content from the 'Episodes from Liberty City' DLC pack.
https://www.notebookcheck.net/Grand-Theft-Auto-4-remaster-reportedly-in-the-works-will-be-launched-sometime-in-2023.578068.0.html