I have the exact same issue on my 11” iPad Air M2. After updating to iPadOS 27.0 developer beta 5 a week ago, Siri reverted to the classic version (not the iOS 18 Apple Intelligence one, but the one before THAT, as I believe you’ve described in your last few replies @nitram1872). And it shows the same “Adding support for Siri is in progress. Siri will be unavailable until the update is complete.” message for me too. My iPad has 60+ GB of free storage and it’s been constantly connected to Wi-Fi. I’ve never let the battery run out (and so it has also had many charging sessions). But still, it’s stuck on this “Siri AI support” download or whatever it is. It might be important to mention that I had stalled on the beta updates since developer beta 2. So I upgraded from beta 2 to 5. But Siri AI was working just fine on beta 1 and 2. Not on 5. It’s probably also important to mention that my M1 iMac (on the same Apple account, connected to the same Wi-Fi network), finished adding support just 2-3 days after updating it to macOS 27.0 developer beta 5, and Siri AI works perfectly fine on the Mac. I updated both my iPad and my Mac to iPadOS 27.0 and macOS 27.0 dev beta 5 on the same day. (Before that, I was also stalling on updating my Mac, I believe it was on dev beta 1 or 2, not exactly sure.)