Hey there, and welcome to Apple Support Communities Pischa,
We can certainly understand your concern and see you came to us from the article Use parental controls on your child's iPhone, iPad, and iPod touch.
To answer your question, yes, you can have issues with older devices using outdated software trying to access new features or features only available in certain versions of iOS. Currently iOS 15.7 is compatible with parental control features. However, as time passes your device will eventually become unsupported and new features might not be available for your system. If you do decide to purchase a new device, check out these steps on how to setup parental controls.
" Set up parental controls with Family Sharing on iPhone
With Family Sharing, the organizer can set up parental controls for children in the Family Sharing group. You can use Screen Time to manage how your children use their Apple devices. You can also turn on Ask to Buy, so children must receive approval for purchases or free downloads.
Learn about types of Family Sharing members.
Customize parental controls during setup
When you add a child to your Family Sharing group or set up a device for a child, you can customize parental controls from the start. You can change those settings at any time.
Follow the onscreen instructions during setup to add any of the following:
- Age-related restrictions for content in apps, books, TV shows, and movies
- Downtime and limits for specific apps
- Restrictions for who your child can communicate with
- Approvals for purchases or free downloads
See the Apple Support article Use parental controls on your child’s iPhone, iPad, and iPod touch. "
For additional information, check out this link: Set up parental controls with Family Sharing on iPhone - Apple Support
Kindest regards!
