Sony has announced plans to discontinue the online support for the 2009 PSP game, Resistance: Retribution come May. All online services for the game, including its eight-player online mode, will cease to work on May 15, 2015. Fair enough—it’s not as if anyone still plays with their PSP (prove me wrong in the comments).
Resistance Retribution isn’t the first game to lose its online support on Sony’s PlayStation Network. Games like Resistance 1, 2 and 3 no longer work online, either.
After May, the only Resistance game to still offer multiplayer support will be the PS Vita title, Resistance: Burning Skies, which was released in 2012.
Insomniac Games has not announced any plans to develop further Resistance games and is unlikely to do so in the future, so it looks like the series has finally run its course.