If you're still holding onto an old Rekordbox 5 license key, remember that it cannot be used to activate Rekordbox 6
If you don't have a Hardware Unlock device, you can still use Rekordbox 6 legally and safely: If you're still holding onto an old Rekordbox
When you plug a compatible Pioneer DJ controller or mixer into your computer, the software automatically detects the device and unlocks PERFORMANCE mode features—no key required. If you're still holding onto an old Rekordbox