Link to developer preview

README.md

@@ -99,7 +99,7 @@ We have three sample apps in this repository:
 
 Get help on our [Q&A board](https://github.com/angular/angularfire/discussions?discussions_q=category%3AQ%26A), the official [Firebase Mailing List](https://groups.google.com/forum/#!forum/firebase-talk), the [Firebase Community Slack](https://firebase.community/) (`#angularfire2`), the [Angular Community Discord](http://discord.gg/angular) (`#firebase`), [Gitter](https://gitter.im/angular/angularfire2), the [Firebase subreddit](https://www.reddit.com/r/firebase), or [Stack Overflow](https://stackoverflow.com/questions/tagged/angularfire2).
 
-> **NOTE:** While relatively stable, AngularFire is considered an early preview and is subject to change before general availability. Questions on the mailing list and issues filed here are answered on a <strong>best-effort basis</strong> by maintainers and other community members. If you are able to reproduce a problem with Firebase <em>outside of AngularFire's implementation</em>, please [file an issue on the Firebase JS SDK](https://github.com/firebase/firebase-js-sdk/issues) or reach out to the personalized [Firebase support channel](https://firebase.google.com/support/).
+> **NOTE:** While relatively stable, AngularFire is a [developer preview](https://angular.io/guide/releases#developer-preview) and is subject to change before general availability. Questions on the mailing list and issues filed here are answered on a <strong>best-effort basis</strong> by maintainers and other community members. If you are able to reproduce a problem with Firebase <em>outside of AngularFire's implementation</em>, please [file an issue on the Firebase JS SDK](https://github.com/firebase/firebase-js-sdk/issues) or reach out to the personalized [Firebase support channel](https://firebase.google.com/support/).
 
 ## Developer Guide