When submission of iOS apps with XCFramework will become mandatory

I searched for Apple guidelines/documentation that indicate when submission of iOS apps with XCFrameworks (instead of the fat frameworks) to AppStore will become mandatory but I didn't find any.

Did I miss it or Apple never stated when it will become mandatory?
To add on top of my original question - will it be mandatory at all?
When submission of iOS apps with XCFramework will become mandatory
 
 
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