This blog post outlines how to revive on iOS using an IPA file. Since Rovio removed the game from the App Store in 2019 to focus on newer titles, sideloading is now the primary way for fans to access this classic RPG.
For Angry Birds Epic , the decryption process is necessary to create a "universal" backup. However, this sits in a legal grey area. The Digital Millennium Copyright Act (DMCA) and similar international laws prohibit the circumvention of effective copy controls, complicating the archival mission.
Reliable community repositories like Archive.org often host "abandonware" versions of the game uploaded by preservationists.
When you bought a game from the App Store, you were essentially downloading an encrypted IPA tied to your Apple ID. Once a game is delisted or "abandonware" (no longer supported by the developer), the only way to access it on a modern device is often via a third-party backup of that IPA file.
Sideloading IPA files can potentially pose risks to your device's security. Make sure to only download files from trusted sources and exercise caution when installing third-party apps.
In late 2023, Rovio was acquired by Sega. There has been no official announcement about relisting old Angry Birds games. However, Sega has a history of re-releasing classic titles (e.g., Sonic 1&2 remasters). It is possible—but not guaranteed—that an “Angry Birds Epic Remastered” could appear in the future.