Flex Plan App
I've gone back to Flex/Momentum recently and looked for an app. I just started using Weight Watchers Diary version 5.0.2 for Android. I believe it's free--otherwise very low cost. You can customize it for Flex/Momentum or for the current WW program. Check You Tube to learn about features. There is another one available as well called I Track Bites, I believe. I didn't think it was as user friendly.
I also like a program called WW Restaurants. it has flex/momentum points as well as those for the current program.
Good luck! It's a great, "flexible" program!