Angular strives to balance innovation and stability.
Sometimes, APIs and features become obsolete and need to be removed or replaced so that Angular can stay current with new best practices, changing dependencies, or changes in the (web) platform itself.
To make these transitions as easy as possible, we deprecate APIs and features for a period of time before removing them. This gives you time to update your apps to the latest APIs and best practices.
Features and APIs that were deprecated in v6 or earlier are candidates for removal in version 9 or any later major version. For information about Angular's deprecation and removal practices, see [Angular Release Practices](guide/releases#deprecation-practices "Angular Release Practices: Deprecation practices").
For step-by-step instructions on how to update to the latest Angular release, use the interactive update guide at [update.angular.io](https://update.angular.io).
To help you future-proof your apps, the following table lists all deprecated APIs and features, organized by the release in which they are candidates for removal. Each item is linked to the section later in this guide that describes the deprecation reason and replacement options.
Tip: In the [API reference section](api) of this doc site, deprecated APIs are indicated by ~~strikethrough.~~ You can filter the API list by [**Status: deprecated**](api?status=deprecated).
| [`defineInjectable`](api/core/defineInjectable) | `ɵɵdefineInjectable` | v8 | Used only in generated code. No source code should depend on this API. |
| [`ViewEncapsulation.Native`](api/core/ViewEncapsulation#Native) | [`ViewEncapsulation.ShadowDom`](api/core/ViewEncapsulation#ShadowDom) | v6 | Use the native encapsulation mechanism of the renderer. See [view.ts](https://github.com/angular/angular/blob/3e992e18ebf51d6036818f26c3d77b52d3ec48eb/packages/core/src/metadata/view.ts#L32).
This section lists all of the currently-deprecated features, which includes template syntax, configuration options, and any other deprecations not listed in the [Deprecated APIs](#deprecated-apis) section above. It also includes deprecated API usage scenarios or API combinations, to augment the information above.
Angular previously has supported an integration with the Web Tracing Framework (WTF) for performance testing of Angular applications. This integration has not been maintained and likely does not work for the majority of Angular applications today. As a result, we are deprecating the integration in Angular version 8.
The shadow-dom-piercing descendant combinator is deprecated and support is being [removed from major browsers and tools](https://developers.google.com/web/updates/2017/10/remove-shadow-piercing). As such, in v4 we deprecated support in Angular for all 3 of `/deep/`, `>>>` and `::ng-deep`. Until removal, `::ng-deep` is preferred for broader compatibility with the tools.
For more information, see [/deep/, >>>, and ::ng-deep](guide/component-styles#deprecated-deep--and-ng-deep "Component Styles guide, Deprecated deep and ngdeep")
The `<template>` tag was deprecated in v4 to avoid colliding with the DOM's element of the same name (such as when using web components). Use `<ng-template>` instead. For more information, see the [Ahead-of-Time Compilation](guide/aot-compiler#enablelegacytemplate) guide.
The [`NgFormSelectorWarning`](api/forms/NgFormSelectorWarning) directive is solely used to display warnings when the deprecated `ngForm` selector is used.
For more information, see the usage notes for [`FormControlDirective`](api/forms/FormControlDirective#use-with-ngmodel) and [`FormControlName`](api/forms/FormControlName#use-with-ngmodel).
In the service worker configuration file `ngsw-config.json`, `versionedFiles` and `files` have the same behavior. As of v6, `versionedFiles` is deprecated; use `files` instead.
In v5, Angular replaced the `ReflectiveInjector` with the `StaticInjector`. The injector no longer requires the Reflect polyfill, reducing application size for most developers.
From https://blog.angular.io/version-5-0-0-of-angular-now-available-37e414935ced
-->
Angular used to rely on the browser to provide number, date, and currency formatting using browser i18n APIs. This practice meant that most apps needed to use a polyfill, users were seeing inconsistent results across browsers, and common formats (such as the currency pipe) didn’t match developer expectations out of the box.
In version 4.3, Angular introduced new number, date, and currency pipes that increase standardization across browsers and eliminate the need for i18n polyfills. These pipes use the Unicode Common Locale Data Repository (CLDR) instead of the JS Intl API to provide extensive locale support.
In version 5.0.0, Angular updated its standard pipes to use the CLRD implementation.
At that time, Angular also added [`DeprecatedI18NPipesModule`](api/common/DeprecatedI18NPipesModule) and related APIs to provide limited-time access to the old behavior. If you need to use these `Deprecated*` pipes, see [Angular change log](https://github.com/angular/angular/blob/master/CHANGELOG.md#i18n-pipes) and the [Date Formats mappings](https://docs.google.com/spreadsheets/d/12iygt-_cakNP1VO7MV9g4lq9NsxVWG4tSfc98HpHb0k/edit#gid=0 "Date Formats Google sheet").
Reminder: If you use these `Deprecated*` pipes, you should migrate to the current APIs listed above as soon as possible. These deprecated APIs are candidates for removal in version 9.
When Angular first introduced lazy routes, there wasn't browser support for dynamically loading additional JavaScript. Angular created our own scheme using the syntax `loadChildren: './lazy/lazy.module#LazyModule'` and built tooling to support it. Now that ECMAScript dynamic import is supported in many browsers, Angular is moving toward this new syntax.
In version 8, the string syntax for the [`loadChildren`](api/router/LoadChildren) route specification was deprecated, in favor of new syntax that uses `import()` syntax.
**Version 8 update**: When you update to version 8, the [`ng update`](cli/update) command performs the transformation automatically. Prior to version 7, the `import()` syntax only works in JIT mode (with view engine).
**Declaration syntax**: It's important to follow the route declaration syntax `loadChildren: () => import('...').then(m => m.ModuleName)` to allow `ngc` to discover the lazy-loaded module and the associated `NgModule`. You can find the complete list of allowed syntax constructs [here](https://github.com/angular/angular-cli/blob/a491b09800b493fe01301387fa9a025f7c7d4808/packages/ngtools/webpack/src/transformers/import_factory.ts#L104-L113). These restrictions will be relaxed with the release of Ivy since it'll no longer use `NgFactories`.
### ActivatedRoute params and queryParams properties
[ActivatedRoute](api/router/ActivatedRoute) contains two [properties](api/router/ActivatedRoute#properties) that are less capable than their replacements and may be deprecated in a future Angular version.
### Dependency on a reflect-metadata polyfill in JIT mode
Angular applications, and specifically applications that relied on the JIT compiler, used to require a polyfill for the [reflect-metadata](https://github.com/rbuckton/reflect-metadata) APIs.
The need for this polyfill was removed in Angular version 8.0 ([see #14473](https://github.com/angular/angular-cli/pull/14473)), rendering the presence of the poylfill in most Angular applications unnecessary. Because the polyfill can be depended on by 3rd-party libraries, instead of removing it from all Angular projects, we are deprecating the requirement for this polyfill as of version 8.0. This should give library authors and application developers sufficient time to evaluate if they need the polyfill, and perform any refactoring necessary to remove the dependency on it.
In a typical Angular project, the polyfill is not used in production builds, so removing it should not impact production applications. The goal behind this removal is overall simplification of the build setup and decrease in the number of external dependencies.
In the following example, the two-way binding means that `optionName`
should be written when the `valueChange` event fires.
```html
<option*ngFor="let optionName of options"[(value)]="optionName"></cmp>
```
However, in practice, Angular simply ignores two-way bindings to template variables. Starting in version 8, attempting to write to template variables is deprecated. In a future version, we will throw to indicate that the write is not supported.
```html
<option*ngFor="let optionName of options"[value]="optionName"></cmp>
```
{@a binding-to-innertext}
### Binding to `innerText` in `platform-server`
[Domino](https://github.com/fgnass/domino), which is used in server-side rendering, doesn't support `innerText`, so in platform-server's "domino adapter", there was special code to fall back to `textContent` if you tried to bind to `innerText`.
These two properties have subtle differences, so switching to `textContent` under the hood can be surprising to users. For this reason, we are deprecating this behavior. Going forward, users should explicitly bind to `textContent` when using Domino.
{@a wtf-apis}
### `wtfStartTimeRange` and all `wtf*` APIs
All of the `wtf*` APIs are deprecated and will be removed in a future version.
{@a platform-webworker}
### `platform-webworker`
The `@angular/platform-*` packages enable Angular to be run in different contexts. Some examples are running Angular on the server (`@angular/platform-server`), in the browser (`@angular/platform-browser`), or in a [web worker](https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API) (`@angular/platform-webworker`).
Though web worker is useful to offload things requiring lots of processing, pushing whole apps to run in the web worker isn't a winning strategy due to many unresolved issues.
Angular CLI doesn't allow use of these APIs because the build system and bundling doesn't support them. This whole package is deprecated in Angular version 8 and will be removed in the future. If you're currently using the `@angular/platform-webworker` APIs in production, please reach out to devrel@angular.io and let us know - we're interested in hearing your use cases.
Instead, use web workers primarily for offloading CPU intensive, but functionally not critical, work needed for initial rendering (for example, in memory search, image processing, and so on).
platform-webworker has been around since the initial release of Angular version 2. It began as an experiment to leverage Angular's rendering architecture and try something different: to run an entire web application in a web worker.
We've learned a lot from this experiment, and have come to the conclusion that pushing entire applications to run in a web worker is not a recipe for success for most applications. This is due to a number of unresolved issues, including:
* Poor or non-existent support for web worker APIs in web crawlers/indexers.
* Poor support in build and bundling tooling.
As a result, as of Angular version 8, we are deprecating the `platform-webworker` APIs in Angular. This consists of both NPM packages, `@angular/platform-webworker` and `@angular/platform-webworker-dynamic`.
Going forward, we will focus our efforts related to web workers around their primary use case of offloading CPU-intensive but not critical work.
| [`@angular/http`](https://v7.angular.io/api/http) | All exports | [`@angular/common/http`](https://v7.angular.io/api/common/http) | See [below](#http). |
[`@angular/http/testing`](https://v7.angular.io/api/http/testing) | All exports | [`@angular/common/http/testing`](https://v7.angular.io/api/common/http/testing) | See [below](#http). |
| `@angular/platform-browser` | [`DOCUMENT`](https://v7.angular.io/api/platform-browser/DOCUMENT) | [`DOCUMENT` in `@angular/common`](https://v7.angular.io/api/common/DOCUMENT) | Updating to version 8 with [`ng update`](cli/update) changes this automatically. |
* Replace `HttpModule` with [`HttpClientModule`](api/common/http/HttpClientModule) (from [`@angular/common/http`](api/common/http)) in each of your modules.
* Replace the `Http` service with the [`HttpClient`](api/common/http/HttpClient) service.
