simple, first you have to create design to show new updates screen is available in each build you upload.
then make api that fill info in updates screen and store flag in device locally, so whenever user open your app new update screen showed.
Yes for this you need to call new version api every time when user open your app or you can use push notification to pass as well.
You have to create to API 1st) api is return currently uploaded version on app store and 2nd) api is to get data that you want to show in your new updates available screen
step 1 : create screen design of update screen in your application.
step 2 : create API that return current version in app store, call this api in your app and check version is same or not.
step 3 : if version is not same than call Data API and store them in locally.
step 4 : if new updates data is available and version not same than show your new updates available screen when user open your app.
step 5 : after user updates app then check version and remove previous loaded data.
