I am using ng2-charts in Angular 7 app and having warning
WARNING in ./node_modules/ng2-charts/fesm5/ng2-charts.js 230:54-72
Right, you have to do npm install ng2-charts@2.2.3 --save
Also, check into your package.json for "ng2-charts": "2.2.3",
I also faced same issue but previously I had "ng2-charts": "^2.2.3", so I removed caret (^). It means "Compatible with version" it will install major version. But use "Fixed version" if you don't want to change version of package on each installation.