Team GO Rocket can now be encountered again in Pokémon GO, Shadow Zapdos will return as an encounter when you defeat Giovanni from June 1 at 12 a.m. until June 17 at 12 a.m. local time

Team GO Rocket is back in Pokémon GO. Read on below to learn more:

Team GO Rocket is back

Trainers,

Thank you for your patience while we addressed the issues with Team GO Rocket. We apologize for their extended absence, and we are letting you know that they are back.

To make up for the time Team GO Rocket was away, Shadow Zapdos will be returning as an encounter when you defeat Giovanni from Tuesday, June 1, 2021, at 12:00 a.m. until Thursday, June 17, 2021, at 12:00 a.m. local time.

Thank you again for your patience and understanding while we worked on this issue.

—The Pokémon GO team

To make up for the time that Team GO Rocket was away, Shadow Zapdos will be returning as an encounter when you defeat Giovanni from Tuesday, June 1, at 12 a.m. until Thursday, June 17, at 12 a.m. local time. https://t.co/7f9pYLxC6N

— Niantic Support (@NianticHelp) April 22, 2021

Trainers, the issue affecting Team GO Rocket battles has been resolved, and Team GO Rocket can again be encountered in game. Thanks for your patience. For more information on this and other bugs, please see our Known Issues page here: https://t.co/erpTzrSedy

— Niantic Support (@NianticHelp) April 22, 2021

Trainers, while we investigate errors associated with Team GO Rocket encounters, they will be temporarily unavailable. We'll update here with more information. We apologize for any inconvenience.

— Niantic Support (@NianticHelp) April 10, 2021

Source: Official Pokémon GO blog