Republican Commissioner Brendan Carr is calling on the Federal Communications Commission to investigate Apple’s response to Beeper Mini — the app that briefly brought iMessage to Android. During the State of the Net Conference on Monday, Carr said the FCC should look into whether Apple’s move “complies with the FCC’s Part 14 rules” about accommodating users with disabilities.

Beeper Mini launched last year, allowing Android users to gain access to iMessage features, including blue message bubbles and the ability to send high-quality photos and videos. However, Apple quickly blocked Beeper Mini users and continued to shut down attempts to make the app work, leading its developers to eventually just give up.

The FCC’s Part 14 rules lay out requirements that “advanced communications service,” such as iMessage, must follow to ensure they’re accessible. By putting a stop to Beeper Mini, Carr argues Apple may violate the FCC’s rule that says providers “shall not install network features, functions, or capabilities that impede accessibility or usability.” He says that the low contrast on the green bubbles “makes it difficult for people with low vision or difficulty with seeing from picking up those messages.”

“Apple made changes to iMessage to disable the functionality of Beeper Mini,” Carr said. “The FCC should launch an investigation to look at whether Apple’s decision to degrade the Beeper Mini functionality that was being provided, which again, encouraged accessibility and usability, was a step that violated the FCC’s rules.” The Verge reached out to FCC Chairwoman Jessica Rosenworcel to see if the agency plans on investigating but didn’t immediately hear back.

It seems like Carr is concerned about more than just the Beeper Mini debacle, though. He also mentioned Apple’s impact on the augmented and virtual reality spaces and criticized the walled garden Apple puts around its products and services. “I think there are potentially negative consequences if Apple perpetuates a world in which it treats its own proprietary technologies one way and degrades the performance of competitive ones,” Carr said.