When I place the command npm update for an existing React project, this is displayed:
npm update
npm WARN deprecated popper.js@1.16.1: You can find the new
npm WARN deprecated popper.js@1.16.1: You can find the new Popper v2 at @popperjs/core, this package is dedicated to the legacy v1
Run the command npm uninstall popper.js && npm i @popperjs/core to remove the deprecated package and install their new Popper v2
npm uninstall popper.js && npm i @popperjs/core