i have just upgraded to 0.26 react-native but showing error.Can u help me on this

I think, update to 0.26-wip could help for now
how to do that can u suggest?
npm i react-native-router-flux@aksonov/react-native-router-flux#0.26-wip
You will have probably more issues due to breaking changes of 0.26 version of https://github.com/facebook/react-native/releases
@gmchaturvedi1
In General ...super expression must be either null.. means that one ore more of your external dependencies are using legacy React import due to breaking changes in RN0.26
Agree with @rturk this is usually because a dependency does import Foo from 'react-native', and then extends Foo.Component, which no longer exists since RN 0.26.
Also things may have stabilized since two days ago, so give the upgrade another try.
Most helpful comment
npm i react-native-router-flux@aksonov/react-native-router-flux#0.26-wip
You will have probably more issues due to breaking changes of 0.26 version of https://github.com/facebook/react-native/releases