So, back on September 6th, 2024, I asked someone on iPhoneOS Obscura if they have the oldest versions of Endless Alphabet, and contributor seychellscollections accepted to to dump the IPA files for the versions. Recently, he uploaded the four earliest versions of the application on the Internet Archive. I downloaded the oldest version, 1.0, and ripped the sounds from that version. Q, T, X and Y's sounds were different from the later versions. Unfortunately, C and I have their updated sounds. Perhaps their original sounds (as seen in the Android trailer) were used in an early build prior to the app's release on the App Store. If you want to play any of the oldest versions, search their IPA files on the Internet Archive, and sideload them onto your jailbroken old iPhone. Please note that the versions require iOS 5.0 and later iOS versions that support 32-bit chips (up until iOS 10, 11 completely dropped support for 32-bit apps).
BIG credits to Seychell's Collections for preserving the versions on the Internet Archive Originator Kids for creating the game
