When it comes to remakes of the main series Pokemon games, Game Freak has mostly stuck to a pretty predictable pattern. In 2004, the company released Pokemon FireRed and LeafGreen for the Game Boy Advance. Then five years later, it released Pokemon HeartGold and SoulSilver for the DS. And then five years after that, in 2014, it launched Omega Ruby and Alpha Sapphire. However, it's been six years since those games, and no Diamond and Pearl remakes have been announced to date.
Pokemon Diamond and Pearl remakes seem like an inevitability, but it remains to be seen when the games will be available. Right now, Game Freak is busy working on the Crown Tundra DLC for Pokemon Sword and Shield, which is expected to launch at some point later this year. However, rumors persist that the company is also busy working on Pokemon Diamond and Pearl remakes, and now a new rumor claims to reveal when fans can expect those games, and a feature they will entail.
According to the rumor, the Pokemon Diamond and Pearl remakes are expected to launch November 2021 for the Nintendo Switch. One look at the Pokemon franchise's release history in recent years makes this a pretty safe bet, and so if the games do exist, November 2021 does seem like one of the most likely release months. Meanwhile, the rumor also says that the Diamond and Pearl remakes will feature Gigantamaxing.
Gigantamaxing is a relatively new feature in the Pokemon franchise, introduced in 2019's Pokemon Sword and Shield. Gigantamaxing allows Pokemon to temporarily transform into massive versions of themselves, but with some significant visual changes. If the rumor is to be believed, the Pokemon Diamond and Pearl remakes will be introducing Gigantamax forms for Claydol, Dragalge, Empoleon, Floatzel, Garchomp, Infernape, Luxray, Mantine, Mismagius, and Torterra.
This rumor stems from 4chan, and so fans should take it with a massive grain of salt. Usually 4chan "leaks" would be immediately discredited, but there have been legitimate Pokemon franchise leaks from the site in the past. In fact, virtually everything to do with Pokemon Sword and Shield leaked on 4chan, with that poster prematurely revealing everything from the starter Pokemon designs to the Gigantamax feature and much more.
If Pokemon Diamond and Pearl remakes are in development, then fans shouldn't expect any official announcement until some point in 2021 at the earliest. Right now, the focus is on the upcoming Crown Tundra DLC, and it wouldn't make sense for Nintendo, The Pokemon Company, or Game Freak to distract fans with Diamond and Pearl remakes just yet.
Pokemon Diamond and Pearl remakes have not been officially announced.