Hey there,

The 9.0.0 release of Angular is here! This is a major release that spans the entire platform, including the framework, Angular Material, and the CLI. This release switches applications to the Ivy compiler and runtime by default, and introduces improved ways of testing components.

How to update to version 9

Visit update.angular.io for detailed information and guidance. To have the best update experience, first update to the final release of Angular 8.

First, update to the latest version of 8

ng update @angular/cli@8 @angular/core@8

Then, update to 9

ng update @angular/cli @angular/core

In order to update your global angular,

npm i -g @angular/cli

Ivy

Version 9 moves all applications to use the Ivy compiler and runtime by default. In addition to hundreds of bug fixes, the Ivy compiler and runtime offers numerous advantages:

• Smaller bundle sizes
• Faster testing
• Better debugging
• Improved CSS class and style binding
• Improved type checking
• Improved build errors
• Improved build times, enabling AOT on by default
• Improved Internationalization

Here’s a breakdown of some of the more notable improvements.

Smaller bundle sizes

The Ivy compiler has been designed to remove parts of Angular that aren’t being used via tree-shaking and to generate less code for each Angular component.
With these improvements, small apps and large apps can see the most dramatic size savings.

Faster testing

Previously, TestBed would recompile all components between the running of each test, regardless of whether there were any changes made to components (for example, through overrides).
In Ivy, TestBed doesn’t recompile components between tests unless a component has been manually overridden, which allows it to avoid recompilation between the grand majority of tests.

Better debugging

Ivy provides you with more tools to debug your applications. When running an application in Dev Mode with the Ivy runtime, angular now offer the new ng object for debugging.

Improved CSS class and style binding

The Ivy compiler and runtime provides improvements for handling styles. Previously, if an application contained competing definitions for a style, those styles would destructively replace each other. With Ivy, the styles are merged in a predictable way.

For more lets hear it from the creators

Credits : Official Announcement 😄