When the time clock is operating online, changing the system time on the time clock mobile device has no affect on punch times.
To prevent time tampering for punches when the time clock is operating offline, we have a setting to detect such tampering, and lock out the app and flag any affected punches as Tampered in the Fareclock Console. This setting is enabled to flag punches by default, but if you want to actually lock the time clock if tampering is detected, you'll want to enable this setting in the Console under Settings => Devices => Defaults, expand the Security Settings section, look for the field titled "Prevent time tampering", set to "Lock" and save. See the following screenshot for illustration:
Note that in some cases, it is possible for there to be a false positive if the device is disconnected from the internet and/or the device does not keep precise time. If your device does have an issue keeping precise time, here are some instructions to try to fix that:
- Android: https://www.androidcentral.com/why-wont-my-phone-keep-right-time
- Apple iOS: http://osxdaily.com/iphone-ipad-wrong-time-fix/
If you still have issues with the device system time being wrong, then you can optionally disable the tamper detection feature.