According to a recent post on the official PlayStation Twitter account, the online multiplayer modes for PS4 and PS5 games will be available to access for free. It will be available starting on December 10 until December 11, 2022.
In order to enjoy this free online multiplayer weekend, players only need to have a PlayStation Network account and a stable internet connection. PS Plus members will not benefit from this but at least they can now play together with their friends who have not subscribed or re-subscribed to the service.
Why the sudden freebie weekend after all this time? It is possible that SIE is trying to gain back more subscribers after they revealed that it had dropped by nearly two million after the big change with the three tier structure. Or maybe it is to celebrate The Game Awards 2022. Who knows.