You could try using git to revert to a commit from before the problem.
Otherwise you could create a new Expo project and compare the files that exist in both projects. In particular app.json and other config files. Also in a managed app you should not have iOS or android directories.
Can you provided a detailed recap of the steps you took to upgrade? As wodin mentioned, if you see ios and android directories in your project now something went wrong.
These are the steps I’ve made to upgrade the project:
Update expo-cli
expo upgrade in the project directory
As @wodin says, I’ve made the updgrade in another branch so the project has the possibility to revert. Also, after the upgrade my projects has iOS and Android directories. Reading in another documentation from Expo, I’ve deleted the iOS and Android directories and compare the app.json created by a new project and could resolve this issue.
Now Expo says Managed Workflow when I run expo build:android. Honestly I don’t have any clue why this happened…