The latest release notes of the Delta emulator app revealed the reason for the icon change.
Delta is a Game Boy emulator for iOS, with an a-shaped icon on the App Store. Recently, the app changed its icon to a disjointed letter ‘a’ after seemingly receiving a threat from another company, photo editing software Adobe. The developers said that Adobe threatened to take them to court unless the emulator’s icon had changed, and they complied to avoid potential issues. At a closer look, the former Delta icon does indeed resemble the Adobe logo, which has been trademarked in the US and other countries.
The full release notes are available to view on the App Store and when you go to search or update the Delta app. There hasn’t been any improvements or additions of features, which could mean that the update is just a quick fix over an icon issue.