Today after launching of IONIC 4 Beta, I updated my IONIC CLI to 4.0.1. After as i was trying to serve one of my IONIC v1 project using

ionic serve mand it was showing below error and warnings to me

ionic serve

ionic-v1 serve --host 0.0.0.0 --port 8100 --lr-port 35729 --dev-port 53703 [v1] 'ionic-v1' is not recognized as an internal or external mand, [v1] operable program or batch file.

[INFO] Looks like @ionic/v1-toolkit isn't installed in this project.

   This package is required for ionic serve. For more details, please see the CHANGELOG:
   .md#4.0.0

[ERROR] A utility CLI has unexpectedly closed.

    The Ionic CLI will exit. Please check any output above for error details.

PLEASE HELP

Today after launching of IONIC 4 Beta, I updated my IONIC CLI to 4.0.1. After as i was trying to serve one of my IONIC v1 project using

ionic serve mand it was showing below error and warnings to me

ionic serve

ionic-v1 serve --host 0.0.0.0 --port 8100 --lr-port 35729 --dev-port 53703 [v1] 'ionic-v1' is not recognized as an internal or external mand, [v1] operable program or batch file.

[INFO] Looks like @ionic/v1-toolkit isn't installed in this project.

   This package is required for ionic serve. For more details, please see the CHANGELOG:
   https://github./ionic-team/ionic-cli/blob/master/packages/ionic/CHANGELOG.md#4.0.0

[ERROR] A utility CLI has unexpectedly closed.

    The Ionic CLI will exit. Please check any output above for error details.

PLEASE HELP

• javascript
• angular
• ionic-framework
• ionic3
• ionic4

• Downgrade your CLI version when you want to use IONIC 1 and when you will use ionic 3 or 4 then you can upgrade it easily. Better and faster way for this case. Here is all versions list npmjs./package/ionic USE: npm install ionic@YOUR_VERSION_NUMBER – Somnath Commented Apr 24, 2019 at 6:57
• I have the same kind of issue, can't run an old ionic v1 project from the last ionic version 6.12.3. How to downgrade and to which version please? – Louis Commented Jan 16, 2021 at 14:35

2 Answers 2

As suggested in warning [INFO] Looks like @ionic/v1-toolkit isn't installed in this project.

I tried to install @ionic/V1-toolkit using below mand and i was able to use ionic serve for my IONIC V1 project from IONIC V4.0.1 CLI.

npm install @ionic/v1-toolkit -g

Install ionic lab

npm install @ionic/lab

This will resolve the issue

Ionic lab doesn’t work with ionic CLI 4.0.0