According to Reddit's iOS Gaming Board, Square Enix seems to have mixed opinions on iOS 8 compatibility updates for The World Ends With You: Solo Remix. User 'chupwn' posted a copy of their support ticket, which reads:
"Unfortunately we have been notified that this title will not be receiving an update to be compatible with iOS 8 and forward. For this we and the development team deeply apologize. We can only suggest that you play the game on an iOS 7 or earlier device at this time. If have purchased the game recently and would like a refund or reimbursement you will need to contact Apple Support as they would act as the retailer in this case. Since we are not the retailer and simply the publisher we would be unable to provide a refund under any circumstances. We apologize for the inconvenience."
Afterwards they received another reply from Square Enix correcting their previous email:
"We apologize, the previous response was premature as our teams have reviewed their response and realized that it was a lot more severe than they meant to provide. They have corrected our notification. This title's patch is more complex than expected and it is taking extra time to patch the game, unfortunately they do not have a final ETA as to when this will be complete."
Currently, The World Ends With You: Solo Remix is simply unplayable on iOS 8 - it gets stuck on an "Initializing" screen. Naturally users are in an uproar over the email and have spoken out on the Reddit message board about Square Enix's performance. 148Apps has reached out to Square Enix for clarification but we have yet to hear back.