Updating Angular Version

 Before updating any existing Angular Project, Please  verify below checklists

1.  Check the current version of the existing APP and compare the changes with the latest APP

From https://update.angular.io/?l=2&v=8.1-11.0 link

This will provide all the updates which needs to be done on existing project

2.  Try ng update command, this command will check the version of all the existing plugins and will give suggestions of some of the plugins to update.

3. Open package.json and update all the suggested versions to be updated.

4. Make sure to update all the existing thirdparty plugins and check all there compatibility with the latest version and update those as well.

It is recommended to always use the Licenced packages and plugins to be used.

5. Run  npm install command to update all the packages and plugins

There are certain warnings which will be notified at the time of updates.

Kindly check those warnings and fix as suggested.

Make sure to delete node_modules and package_lock.json files before installing new versions.

6. Create all the checklists of the modules and components on which the changes are required and have impact on the project.

For example:

Renderer class is deprecated from Angular9.

Some for IE-10,11 and IE mobile is removed

7. Update the existing documents and start using the latest version progressively or gracefully without having less impact on project deliveries and performance.