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To protect access to Logbook Pro such as kids, friends, family members, etc. and protect the data from within from anyone tampering without your knowing you can tell iOS to prompt for the iOS passcode or use Touch , Touch ID, or Face ID if supported by the device when opening Logbook Pro. In the Security section as shown above set "Require Authentication" ON. The "Require" option allows you to control how often you are prompted for the passcode, Touch ID, or Touch Face ID such as every time Logbook Pro is opened or after a period of time.
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