ANGULAR 2 is not just a typical UPGRADE but a totally NEW development. The whole framework is rewritten from the ground. Angular 2 got rid of many things like $scope, controllers, DDO, jqLite, angular.module etc.

It uses components for almost everything. Imagine that even the whole app is now a COMPONENT. Also it takes advantage of ES6 / TypeScript syntax. Developing Angular 2 apps in TypeScript has made it even more powerful.

Apart from that, many things have EVOLVED and re-designed like the template engine and many more.

Angular 2 is not just a typical upgrade but a totally new development. The whole framework is rewritten from the ground. Angular 2 got rid of many things like $scope, controllers, DDO, jqLite, angular.module etc.

It uses components for almost everything. Imagine that even the whole app is now a component. Also it takes advantage of ES6 / TypeScript syntax. Developing Angular 2 apps in TypeScript has made it even more powerful.

Apart from that, many things have evolved and re-designed like the template engine and many more.