BERLIN: If you have youngsters who play games on their smartphones, then check these are not costing you cash on the sly as many games that appear to be free actually involve players spending money to unlock additional features.

That might not be clear to younger players, say crime prevention experts at Germany's police. They advise that parents deactivate in-app purchases altogether by adjusting the basic settings in the app store.

If you have an android phone, head to the Play Store and go to "settings," then go to "authentication." Here you can select that all purchases must first be authenticated.

On iOS, you can disable in-app purchases in your settings by heading to "Screen time" and disallowing "Purchases in iTunes & App Store." If you want to change the setting in the future, you have to select a four-digit code.

 - dpa