3.15 release post, Octane is Here post

source/2019-12-20-ember-3-15-released.md

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+---
+title: Ember 3.15 "Octane" Released
+author: Kenneth Larsen, Matthew Beale, Melanie Sumner
+tags: Releases, 2019, 3, 3.15, Version 3.x
+alias: 2019-12-20-ember-3-15-released.md
+responsive: true
+date: "2019-12-20 16:30:00 -0500"
+---
+
+Today the Ember project is releasing version 3.15 of Ember.js, Ember Data, and
+Ember CLI. In addition to brining new features and bug fixes, Ember 3.15 also marks the official release of the [Octane edition](TODO://link-to-octane-blog-post), which is Ember's first [edition release](https://emberjs.com/editions/).
+
+<!--alex ignore just-->
+Ember developers using the Octane edition can exercise modern features like native ES
+classes, decorators, the new Glimmer component API, and a new approach to state
+management called tracked properties. Combined, these innovative changes to
+Ember are more than just new tools and APIs. Octane's features, together,
+sum up to a paradigm shift in how Ember applications are built.
+
+READMORE
+
+<!--alex ignore nuts-->
+**Read more about how Octane makes web application development fun and
+productive in 
+[Octane is Here](https://blog.emberjs.com/2019/12/20/octane-is-here.html), a blog post from Yehuda.**
+
+...and then explore our completely updated and refreshed guide and API
+documentation:
+
+* Check out the completely rewritten [core concepts section](https://guides.emberjs.com/release/components/) in the guides.
+* Read the [completely updated Super Rentals tutorial](https://guides.emberjs.com/release/tutorial/).
+* Already using Ember and want to adopt Octane? See the [Octane Upgrade
+  Guide](https://guides.emberjs.com/release/upgrading/current-edition/) for the most complete
+  documentation.
+
+In addition to the Octane release, today you can also find version 3.16-beta.1
+released for Ember.js, Ember Data, and Ember CLI. As always we encourage our
+community (especially addon authors) to help test these beta builds and report
+any bugs before they are published as a final release in six weeks' time.
+
+You can read more about Ember's general release process at the [Release Dashboard](http://emberjs.com/builds/).
+
+---
+
+## Other Changes in Ember.js 3.15
+
+Deprecations are added to Ember.js when an API will be removed at a later date. Each deprecation has an entry in the deprecation guide describing the migration path to a more stable API. Deprecated public APIs are not removed until a major release of the framework.
+
+Consider using the [ember-cli-deprecation-workflow](https://github.com/mixonic/ember-cli-deprecation-workflow) addon if you would like to upgrade your application without immediately addressing deprecations.
+
+There were three deprecations in ember.js v3.15.0.
+
+### Deprecate `Component#isVisible` (1 of 3)
+
+Classic Ember components support using the `isVisible` property to toggle the
+visibility of a component's root element. This API was very common in early
+Ember 1.x applications but is rare today. In practice use of template bindings
+has supplanted use of the `isVisible` API.
+
+`isVisible` is deprecated as of Ember 3.15. 
+
+To transition away from this, we recommend using conditionals in a template:
+
+```handlebars
+{{#if this.showComponent}}
+  <MyComponent />
+{{/if}}
+
+{{! or }}
+<div hidden={{this.isHidden}}></div>
+
+```
+
+See the [deprecation guide for
+`isVisible`](https://deprecations.emberjs.com/v3.x#toc_ember-component-is-visible)
+for more information.
+
+### Deprecate `{{partial}}` (2 of 3)
+
+As of the introduction of [template-only
+components](https://api.emberjs.com/ember/3.15/classes/Component)
+and [Glimmer
+components](https://api.emberjs.com/ember/3.15/modules/@glimmer%2Fcomponent),
+as well as of the
+[template-only-glimmer-components](https://guides.emberjs.com/release/configuring-ember/optional-features/#toc_template-only-glimmer-components)
+optional feature the `{{partial}}` API in Ember no longer provides any unique
+benefits. Instead it has several downsides including difficult to teach scoping 
+rules and poor performance.
+
+See the [deprecation guide for
+`{{partial}}`](https://deprecations.emberjs.com/v3.x#toc_ember-partial) for
+an example of how to migration existing use to component APIs.
+
+### Deprecate intimate `window.ENV` API (3 of 3)
+
+Ember applications long ago shifted to using `window.EmberENV` as the home of
+various configuration options. As of 3.15 application code which uses `window.ENV`
+for Ember configuration values will cause a deprecation warning to be issued.
+Support for this intimate API will be removed in 3.17.0.
+
+See [emberjs/ember.js#18441](https://github.com/emberjs/ember.js/pull/18441)
+for more details about this deprecation.
+
+For more details on changes in Ember.js 3.15, please review the [Ember.js 3.15.0 release page](https://github.com/emberjs/ember.js/releases/tag/v3.15.0).
+
+## Ember Data
+
+Ember Data is the official data persistence library for Ember.js applications.
+
+There were two new features and no deprecations for EmberData v.3.15.0.
+
+### Identifiers (1 of 2)
+
+Identifiers provides infrastructure for handling identity within ember-data to satisfy
+requirements around improved caching, serializability, replication, and handling of
+remote data.
+
+For more information read [RFC-403 Identifiers](https://github.com/emberjs/rfcs/blob/master/text/0403-ember-data-identifiers.md).
+
+### Inspector Support is now optional in production (2 of 2)
+
+EmberData ships with a `DataAdapter` which provides the necessary support for
+the data panel in the [Ember Inspector](https://github.com/emberjs/ember-inspector).
+
+This package adds roughly .6 KB when minified and compressed to your application
+in production; however, you can now opt out of shipping this addon in production
+via options in `ember-cli-build.js`
+
+```js
+let app = new EmberApp(defaults, {
+  emberData: {
+    includeDataAdapterInProduction: false
+  }
+});
+```
+
+When using `ember-data` as a dependency of your app, the default is to ship the
+inspector support to production.
+
+When not using `ember-data` as a dependency but instead using EmberData via
+declaring specific `@ember-data/<package>` dependencies the default is to not
+ship to production.
+
+For additional details on changes in Ember Data 3.15.0, please review the full
+[Ember Data 3.15.0 change log](https://github.com/emberjs/data/blob/release/CHANGELOG.md#release-3150-december-18-2019).
+
+## Ember CLI
+
+Ember CLI is the command line interface for managing and packaging Ember.js applications.
+
+There were some noteworthy changes in `ember-cli` to support the release of the Octane edition of Ember. The `@glimmer/component@1.0.0` package was added as a dev dependency for both apps and addons, Octane-related optional features were enabled, `ember-template-lint` was updated to use the `octane` edition preset, and all packages were updated to their latest version in the application blueprint! 
+
+The new addon blueprint also dropped the Ember 3.4 ember-try scenario, but dropping support for existing addons should be considered a breaking change. Existing addons should either keep the scenario, or do a major version bump if they drop support for older Ember versions.
+
+For additional details on the changes in Ember CLI 3.15.0 and detailed upgrade
+instructions, please review the [Ember CLI 3.15.0 release page](https://github.com/ember-cli/ember-cli/releases/tag/v3.15.0).
+
+## Thank You!
+
+As a community-driven open-source project with an ambitious scope, each of these releases serve as a reminder that the Ember project would not have been possible without your continued support. We are extremely grateful to our contributors for their efforts.