How to Fix "This iPhone xx is running iOS 13.3.1 (17D50), which may not be supported by this version of Xcode."

13.3.1 = iOS version number
(17D50) = build number

Solutions:

Step 1: Download iOS version 13.3.1 (17D50) from github
Step 2: Unzip downloaded file
Step 3: Close Xcode
Step 4: Go to Application Folder and Find Xcode;
Step 5: Right click on Xcode and click on "Show Package Content";
Step 6: Then, go to Contents -> Developer -> Platforms -> iPhoneOS.platforms -> DeviceSupport
Step 7: Now, drag and drop the updates device support file to the old Xcode Device support folder and restart the Xcode. This should have fixed the error