AngularJS and Angular are two different frameworks for building web applications using JavaScript. Although they share some similarities in their syntax and structure, there are several important differences between them:

1. Architecture: AngularJS is based on the Model-View-Controller (MVC) architecture, while Angular is based on the more modern and modular Model-View-ViewModel (MVVM) architecture.
2. Language: AngularJS is written in JavaScript, while Angular is written in TypeScript, a superset of JavaScript that adds optional static typing and other features.
3. Syntax: AngularJS uses a two-way data binding syntax, where changes to the model are reflected in the view and vice versa. Angular, on the other hand, uses a unidirectional data flow syntax, where changes to the model are propagated to the view through a series of components.
4. Performance: Angular is generally considered to be faster and more performant than AngularJS, due in part to its use of a more modern architecture and its improved change detection algorithm.
5. Community: Angular has a larger and more active community than AngularJS, which means that it has more resources, documentation, and support available.
6. Migration: Due to the major differences in architecture and syntax between AngularJS and Angular, migrating from one framework to the other can be a complex and time-consuming process.

Overall, Angular is a more modern and feature-rich framework than AngularJS, and it is generally recommended for new projects. However, if you are already using AngularJS and your application is working well, there may be no need to migrate to Angular unless you require specific features or performance improvements.