flutter CocoaPods could not find compatible versions for pod "firebase_core code example

Example 1: CocoaPods could not find compatible versions for pod "Firebase/Messaging":

I had the same problem, but I solved it like this

rm Podfile.lock
pod install --repo-update

Example 2: CocoaPods could not find compatible versions for pod "razorpay_flutter" when running pod install

CocoaPods could not find compatible versions for pod "razorpay_flutter" when running pod install

This is due to your minimum deployment target being less than iOS 10.0. To change this, open ios/Podfile in your project and add/uncomment this line at the top:

# platform :ios, '9.0'
change to 

platform :ios, '10.0'