License Key - Nine Email

Some users purchased a standalone license key before Google managed subscriptions. In this case:

4.1. Data Flow

Server validates against database.

App receives response -> LocalDataSource encrypts and saves license_token and expiry_date to SharedPrefs/SQLite.

4.2. Security Measures

POST /api/license/validate
Request:
"license_key": "9F3K2-MN8B7-VC6X9-ZL4M2",
  "device_id": "abc123",
  "app_version": "3.25"
Response (success):
"valid": true,
"product": "Pro",
"expires": "2026-12-31",
"max_devices": 5,
"current_devices": 2

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Sometimes users buy the license, but the app still asks for a key. Here is how to fix it.

Issue 1: "License verification failed"

Issue 2: I have a key code from a previous device, but the new phone asks for it.

Issue 3: I lost my email with the key.