Migration from legacy iOS App II (Inter-app)

[mneuwert]

This is a follow up #270 which covered the migration during the update when bundle ID remains same. This one covers the scenario when data (settings, accounts) is transferred between two apps.

Unbranded ==> Inter-App Migration

Singleaccount / Multiaccount

Basic Auth ==> Basic Auth

Basic Auth ==> OAuth 2.0 (in case oauth2 enabled on server)

OAuth 2.0 ==> OAuth 2.0

Multiaccount: Indicator that user interaction is required? (in list AND on login page with explanation)

Basic Auth:

Extended Error Message (App Passwort, 2FA => Better use OAuth 2.0)

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Needed Data

Accounts
URL
Method
Name
Username

Recognize new iOS-App

Check via URL-Scheme?

Unlock 1 IaP with old iOS app

How to Import Data

Plist
Key-Value Sharing
Keychain-Sharing

What about different App Store accounts ??

[mneuwert]

Clarification

How to import data

Since the apps live in different developer accounts, we can't neither establish a shared app group nor create shared iCloud container where we could use the key-value store. So, if I am not overlooking anything we could only use good old open-app with registered URL scheme.

Proposal

• So, new app would detect that the legacy app is installed, generate a random K and pass it to the legacy app via open URL method.
• Legacy app would fetch accounts from it's SQLite based data store, get the settings, put them into some sort of data structure (JSON, PLIST etc), encrypt it with the key and pass it back to the app.

Open questions

• Shall we set a passcode in the new app if it was in the legacy ones?
• Shall we migrate authorisation tokens as we did in in-app migration? Or rather force user to re-login?
• We need to coordinate both app's releases since we have to roll out compatible migration changes in both apps. I think legacy app can be tested and released first..

Notes

• Use app identifiers for URL schemes used for migration.