The version of CocoaPods used to generate the lockfile (1.5.3) is higher than the version of the current executable (1.5.2)

The error you are getting is due to your podfile.lock being built with an older version of Cocoapods. All you need to do is to delete your podfile.lock file and run pod install. This will create a new podfile.lock, with your current dependencies. Note that it should not take too long because your files should already be downloaded, they just need to be linked in said file.

2 solution

1. deleted ios/podfile.lock and again do $pod install

OR

2. OS UPDATE

   2.1 updated mac to high sierra or higher

   2.2 update xcode

   2.3 then update pod $sudo gem install cocoapods

   2.4 then $cd ios

   2.5 then $pod install

   2.6 $react-native start-ios

For those like me whose cocoapods version is 1.5.2, you can update cocoapods using

sudo gem install cocoapods

and the problem is solved

For checking pod version use

pod --version

For those for which cocoapods version is 1.5.3, you can delete podfile.lock and do pod install. However please note that if the version, of libraries used in your project, is not specified in podfile, then they will be automatically updated to latest vesrion.