For now, Apple has started publicly testing iOS 26 through its beta program, starting with developers. Reports suggest that the size of the iOS 26 Developer Beta 1 is 15GB.

After you sign up for the Apple Developer program, you should see the option to download the iOS 26 developer beta in your settings.

How to Download iOS 26 Developer Betas The option to download and install the iOS 26 Developer Beta is immediately available for users who have previously enrolled on Apple's Beta Software Program.

How to Install macOS Tahoe Developer Beta If you haven't already, register your Apple Account with the Apple Developer Program (it's free) over at developer.apple.com.

GitHub Developer Programは、2015年より有料アカウントを持つ開発者向けに提供されていたプログラム。 GitHub APIの変更通知、新機能の試用などが行える。