I got a notice to update to iOS 27.2 this morning (Australia). The splash screen referred to Siri AI but I was more interested in the security updates so went ahead. Then I saw that it was more than 12Gb. My iPhone has taken more than 40 minutes to complete the update. I haven’t tried various apps yet and I am not enabling Siri AI but this update might be a challenge for some devices with less memory.
More info about the update here:
Some users are reporting 18Gb downloads and taking hours to download. Apple’s servers must be stretched.