Error: Schema validation failed with the following errors: Data path “” should NOT have additional properties(project)

Question

After migrating application from angular 5 to 6, on running ng serve the following errors pop up.

Schema validation failed with the following errors:

Answer 1

Angular Upgrade from 9 to 10 is very easy (all additional detail-information is here: https://update.angular.io/?v=9.0-10.0) :

Make sure your package file is in version control and all changes have been committed. This will overwrite your package file. Better you try it in a new experimental branch.

npm install -g npm-check-updates
ncu -u
ng update --all --force

In the new schema, it is no more allowed to use the key es5BrowserSupport, remove the following line in your angular.json:

"es5BrowserSupport": true

then simple start your application anew:

npm start