So in the App Store Connect In-app purchase manage, Offer Codes tab, we can see offers with Offer Code URL like this format:
(1) https://apps.apple.com/redeem?ctx=offercodes&id=YOUR_APP_ID&code=CODE
When I implement this URL, my iOS 11.0 device can not open to redeem page of the App Store (It showed "Can not connect to App Store"). But other devices with iOS 12.0 and above worked fine.
When researching I found this URL :
(2) tms-apps://buy.itunes.apple.com/WebObjects/MZFinance.woa/wa/freeProductCodeWizard?code=YOUR_CODE.
which is also open the redeem page of the App Store. And it worked for all of my devices. So should I use this? And what is the difference between (1) and (2)?