This version of CLI is only compatible with Angular versions ^15.0.0, but Angular version 8.1.3 was found instead.

When working on an existing Angular project, I typically review all the project details and execute the "npm install" command in the terminal to install all the necessary modules. However, upon attempting to run the project using a CLI command, an error is displayed.

This version of CLI is only compatible with Angular versions ^15.0.0, but Angular version 8.1.3 was found instead.

 Following that, I navigated to the project's package.json file and discovered that the project was developed using Angular version 8.1.3.

There are two potential ways to address this issue:

1.       Upgrade your Angular project to a newer version that aligns with the Angular CLI version you have installed.

2.       Downgrade the Angular CLI version to a version that supports your current Angular version.

Let's delve into each of these methods in more detail.

·         upgrade your project to use a newer version of Angular : To upgrade your Angular project, you can follow the steps outlined in the Angular documentation for upgrading to a newer version: https://update.angular.io/

 

General step that to be followed to update the project

a.       Check the compatibility: Review the official Angular documentation to ensure that the version you are upgrading to is compatible with your application.

b.       Update Angular CLI: Update the Angular CLI to the latest version by running the following command in your terminal or command prompt: ng update @angular/cli

c.       Update Angular Core: Update the Angular Core package to the latest version by running the following command in your terminal or command prompt: ng update @angular/core

d.       Update dependencies: Review and update other dependencies in your package.json file, as necessary.

e.       If we are using any third party library let say material and other then we need to be update that with newer version

f.       Fix any errors: Review your application and fix any errors that occur as a result of the updates.

g.        Run tests: Run your application's tests to ensure that everything is working as expected.

h.       Update Angular Language Service: If you are using Angular Language Service, update it to the latest version by running the following command in your terminal or command prompt: ng update @angular/language-service

i.       Update other Angular packages: If you are using any other Angular packages, such as @angular/router or @angular/forms, update them to the latest version by running the appropriate ng update command.

·         downgrade the Angular CLI version : To downgrade the version of our project we can run the following commands on CLI.

npm uninstall -g @angular/cli

 

Then, install a specific version of the CLI that is compatible with your Angular version using the following command:

 

npm install -g @angular/cli@<version>

 

Replace <version> with the version number of the CLI that is compatible with your Angular version, for example:

 

npm install -g @angular/cli@8.1.3

 

After installing the compatible version of the CLI, you should be able to use it with your current version of Angular.

 

In my personal opinion, if you are assign or work with previous version of angular project you must try to downgrade your angular CLI version because sometime upgrading will causing issue because some of the libraries are not compatible with newer version.