Add a YubiKey as a Factor to an Existing Database

To add a YubiKey as a factor to an existing KeePass database, simply do the following:

On iOS

1. Unlock the existing database as normal
2. Tap the Circle button in the top right corner
3. Tap ‘Set Master Credentials’
4. Here you can completely set any or all the 3 possible factors:
   1. Password
   2. Key File
   3. YubiKey
5. When you are happy just tap ‘Set’ in the top right corner.

On MacOS

1. Unlock the existing database as normal
2. Click on the Database menu item at the top of your screen
3. Click 'Change Master Credentials'
4. Here you can completely set any or all the 3 possible factors:
   1. Password
   2. Key File
   3. YubiKey
5. When you are happy just click ok.

It is important that you know your YubiKey secret just in case you lose the key. It won't be possible to recover from key loss without a backup key or the secret it was programmed with.