In the WWDC event in June, Apple gave out HTML5 guidelines for their iOS apps. Today, the Cupertino-based company officially extends the timeframe for developers until March of 2020.
In a developer site post, Apple declared the extension as well as reiterating the new guidelines for the App Store. Apple mentions that to provide a secure experience, developers must be in self-contained bundles, which means that the app’s functionality and core features must be within the software binary rather than having to refer users to external sources, including HTML5.

The post mentioned that apps that provide dynamic functionality and core features with HTML5 are better in Safari compared to being distributed via the App Store.
Apple has asked that all new apps meet the specified guideline and urged them to update it as soon as possible. The company has added 6 months for those who need more time to be compliant.