User Configuration > Administrative Templates > Microsoft Word 2016 > Word Options > Security > Cryptography
User
HKCU\software\policies\microsoft\office\16.0\word\security\crypto
This policy setting allows you to specify the encrypted database compatibility. If you enable this policy setting, the compatibility format specified will be applied during encryption for new files - Use legacy format - Use next generation format - All files save with next generation format If you disable or do not configure this policy setting, the default setting, "Use next generation format," will be applied.