2. Identify customers still using old API
3. Identify the active customers still conducting business
4. Send the active customers a migration strategy advising they update this year
5. 3 months later, set a deadline of 6 months to update
6. Send frequent reminders as deadline approaches
7. Put a 'wall' in the dashboard requiring remaining customers update before they can enter reports etc
8. 3 months later remove deprecated API and freeze accounts still using them