expo is out of date uninstall and run again to upgrade

Please, try this:

1.- npm cache clean -f
2.- yarn upgrade
3.- npm upgrade
3.- npm install

If this doesn't work try edit package.json:

{
  "react-native": "https://github.com/expo/react-native/archive/sdk-34.0.0.tar.gz",
  "expo": "^34.0.1",
  "react": "16.8.3"
} 

Then

npm install

let me know if this works for you

Homebrew update sovled my probolem!

brew upgrade node

Expo seems to detect the outdated version and suggests to update it for you in the console when you run expo start:

› Opening exp://192.168.1.231:19000 on Pixel_3a_API_30_x86
✔ Expo Go on Pixel_3a_API_30_x86 (emulator) is outdated, would you like to upgrade? … yes
Uninstalling Expo Go from Android device.

All I had to do was to press Y and it updated automatically.

The issue is to do with the app that is on the iOS simulator / device is out of date and is not compatible with the current version of Expo that you running.

Delete the Expo app from the the iOS simulator and it should work, or install the latest update if you are on a device

https://github.com/expo/expo/issues/1595

One way to do it is with the simulator open is to Erase All Content and Settings. Then re-run npm start and the Expo App will be installed again on this device simulator.