Screen shots will work. But if there is any problem with the FP when they scan the screen shot, there may be an issue if they can’t confirm it on the app itself. The reason for that is that you could theoretically book a FP, take a screen shot, then cancel that FP and book another one in its place. The screen shot would show the first FP but when the screen shot was scanned, it would show that the FP was cancelled. For this reason, some CMs won’t take a screen shot as a valid FP if the computer says it is invalid. If you have it actively showing on the app and there is an issue when you scan in , the CM will usually just override the issue and let you on. I screen shot every FP as soon as I book it, however, because last year the entire FP system went down for several hours, and the only way we were able to use our FPs was with the screen shots (the app went down).