In a pair of late-night Tweets, posted just four minutes apart, Musk expressed concerns about Apple’s business practices, specifically those surrounding Spotify and app store guidelines.

The first was a reply to Spotify founder Daniel Ek’s tweet highlighting a New York Times story about Apple’s three-time rejection of Spotify’s new app, as the streaming service adds audiobooks to its offerings. Apple says the new app violates its rules detailing how developers communicate with customers about online purchases.

Ek used the story as a launching pad to decry the policies, saying “I can’t be the only one who sees the absurdity.” Musk seemed to agree, replying “Concerning.”

Moments later, he voiced support for venture capitalist Bill Lee’s criticism of Apple’s 30% fee for in-app purchases, agreeing “30% is a lot.”

Criticisms about Apple and its app store policies are nothing new, of course. Spotify has butted heads with Apple before, when it began offering podcasts. And Epic Games took Apple to court last year over the policies, resulting in a split decision where the judge upheld the app store’s structure as legal.

Musk loves a good fight, though, and this isn’t the first time he’s poked Apple. In May, he tweeted that “Apple’s store is like having a 30% tax on the internet. Definitely not ok,” following that up with “Literally 10 times higher than it should be.”

And in July 2021, during a Tesla earnings call, he discussed plans allowing competitors to use the company’s electric vehicle charging network, saying: “We do want to emphasize that our goal is to support the advent of sustainable energy. It is not to create a walled garden and use that to bludgeon our competitors which is used by some companies.”

He then faked a cough and added “Apple.”

So do Musk’s new criticisms of Apple mean he’s reviving the (somewhat one-sided) feud? It’s possible. Tesla and Apple have lured employees from each other in the past—and Musk tried to speak with Apple about possibly buying Tesla in the automaker’s early days, but Tim Cook refused the meeting.

Apple, as it has in the past, did not respond publicly to Musk’s comments.