Data Handling After Premium Account Expiry

1. Account Downgrade: Premium (including educational) accounts downgrade to regular, subject to regular account restrictions.
2. Data Retention: Data won't be deleted, even if usage exceeds regular account capacity.
3. Note Usability: Notes can still be used (created, modified, deleted, read) after downgrade.
4. Upload Limitation: Can't upload new files when usage exceeds regular account limits.