Support and FAQ
What is free and what is Pro?
Free forever: 22 complete devices (with parts, steps, science, numbers, facts and safety), every physics principle and the glossary. Kayf Pro, a single one-time purchase, unlocks all 92 devices, the troubleshooting guides, every quiz and device comparison.
I bought Pro but it shows as locked
Open Settings and tap Restore Purchases while signed in with the Apple ID that made the purchase. Family Sharing is enabled for the purchase.
How do I switch language?
Settings, Language. The whole app, including right-to-left layout, switches immediately.
I found a mistake
Please email us with the device name and the section. Corrections ship in the next update.