Ionic error message: Unsupported engine package: '@angular/cli@11.1.4'

Error message:

npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '@angular/cli@11.1.4',
npm WARN EBADENGINE   required: { node: '>= 10.13.0', npm: '^6.11.0', yarn: '>= 1.13.0' },
npm WARN EBADENGINE   current: { node: 'v12.5.0', npm: '7.8.0' }
npm WARN EBADENGINE }
npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '@angular-devkit/architect@0.1101.4',
npm WARN EBADENGINE   required: { node: '>= 10.13.0', npm: '^6.11.0', yarn: '>= 1.13.0' },
npm WARN EBADENGINE   current: { node: 'v12.5.0', npm: '7.8.0' }
npm WARN EBADENGINE }
npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '@angular-devkit/core@11.1.4',
npm WARN EBADENGINE   required: { node: '>= 10.13.0', npm: '^6.11.0', yarn: '>= 1.13.0' },
npm WARN EBADENGINE   current: { node: 'v12.5.0', npm: '7.8.0' }
npm WARN EBADENGINE }
npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '@angular-devkit/schematics@11.1.4',
npm WARN EBADENGINE   required: { node: '>= 10.13.0', npm: '^6.11.0', yarn: '>= 1.13.0' },
npm WARN EBADENGINE   current: { node: 'v12.5.0', npm: '7.8.0' }
npm WARN EBADENGINE }
npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '@schematics/angular@11.1.4',
npm WARN EBADENGINE   required: { node: '>= 10.13.0', npm: '^6.11.0', yarn: '>= 1.13.0' },
npm WARN EBADENGINE   current: { node: 'v12.5.0', npm: '7.8.0' }
npm WARN EBADENGINE }
npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '@angular-devkit/core@11.1.4',
npm WARN EBADENGINE   required: { node: '>= 10.13.0', npm: '^6.11.0', yarn: '>= 1.13.0' },
npm WARN EBADENGINE   current: { node: 'v12.5.0', npm: '7.8.0' }
npm WARN EBADENGINE }
npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '@angular-devkit/schematics@11.1.4',
npm WARN EBADENGINE   required: { node: '>= 10.13.0', npm: '^6.11.0', yarn: '>= 1.13.0' },
npm WARN EBADENGINE   current: { node: 'v12.5.0', npm: '7.8.0' }
npm WARN EBADENGINE }
npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '@schematics/update@0.1101.4',
npm WARN EBADENGINE   required: { node: '>= 10.13.0', npm: '^6.11.0', yarn: '>= 1.13.0' },
npm WARN EBADENGINE   current: { node: 'v12.5.0', npm: '7.8.0' }
npm WARN EBADENGINE }
npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '@angular-devkit/core@11.1.4',
npm WARN EBADENGINE   required: { node: '>= 10.13.0', npm: '^6.11.0', yarn: '>= 1.13.0' },
npm WARN EBADENGINE   current: { node: 'v12.5.0', npm: '7.8.0' }
npm WARN EBADENGINE }
npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '@angular-devkit/schematics@11.1.4',
npm WARN EBADENGINE   required: { node: '>= 10.13.0', npm: '^6.11.0', yarn: '>= 1.13.0' },
npm WARN EBADENGINE   current: { node: 'v12.5.0', npm: '7.8.0' }
npm WARN EBADENGINE }
npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '@stencil/core@2.5.2',
npm WARN EBADENGINE   required: { node: '>=12.10.0', npm: '>=6.0.0' },
npm WARN EBADENGINE   current: { node: 'v12.5.0', npm: '7.8.0' }
npm WARN EBADENGINE }  

Solution:

$ npm -v
7.5.0

$ npm install --global npm@6

removed 60 packages, changed 194 packages, and audited 436 packages in 30s

3 packages are looking for funding
  run `npm fund` for details

found 0 vulnerabilities

$ npm -v
6.14.11

$ npm install -g @angular/cli
npm WARN deprecated request@2.88.2: request has been deprecated, see https://github.com/request/request/issues/3142
npm WARN deprecated har-validator@5.1.5: this library is no longer supported
/usr/local/bin/ng -> /usr/local/lib/node_modules/@angular/cli/bin/ng

> @angular/cli@11.1.4 postinstall /usr/local/lib/node_modules/@angular/cli
> node ./bin/postinstall/script.js

? Would you like to share anonymous usage data with the Angular Team at Google u
nder
Google’s Privacy Policy at https://policies.google.com/privacy? For more details
 and
how to change this setting, see http://angular.io/analytics. Yes

Thank you for sharing anonymous usage data. If you change your mind, the following
command will disable this feature entirely:

    ng analytics off

+ @angular/cli@11.1.4
added 5 packages from 2 contributors, removed 7 packages and updated 234 packages in 103.594s
————————————————