As per the new announcement on the Apple Developers website, developers can now create and implement their own custom codes, (for example- NEWPROMO)
Previously to boost in-app subscriptions for developers, Apple introduced new ways like special discount codes. However, earlier discount codes were generated randomly and were of one-time use. Those one-time codes still remain available along with custom codes.
For detailed info on the insight visit - https://www.markovate.com/news/custom-offer-codes-available-apple/
