GermanHelp article
What does "The developer needs to update this app..." mean on iOS?
For older published versions of an app, problems can now occur under current iOS versions and reduce the speed due to the lack of 64-bit support. Even if the content within the app is up to date, the basic version has already been in the AppStore for a certain amount of time and is now being criticized by Apple directly to users accordingly. This mostly affects apps running iOS, with a published date from before June 2015.
According to current statements from Apple, there is sometimes the risk that these are automatically removed from the store operator after a certain period.
In this case, you should now specifically in the app management under "AppStores & Co." order a new release. After the re-release, we will pass all the details for the update to Apple in the short term, so that the app will be made available to all app users in a new version in about 1 to 3 business days.
In the course of this, among other things, new push modules and other relevant areas will be exchanged, so that this starts significantly faster. In the context, there is also an update of the Google Play Android app.