Ember 3.8 Brings New Features And Important Fixes

Along with some important fixes in Ember.js, Ember Data, and Ember CLI; this release brings two new features in Ember.js: element modifier manager and array helper.

Recently, The Ember project team released version 3.8 of the Ember.js, Ember Data, and Ember CLI. 
According to the company, the 3.8.0 release is an Ember.js Long-Term Support candidate. This release is incremental, backward compatible and brings two new features: element modifier manager and array helper.
version 3.8 of Ember.js, Ember Data, and Ember CLI 
Source: Ember 
Element modifier manager is a very low-level API, which is responsible for coordinating the lifecycle events that are triggered when an element modifier is invoked, installed, and updated.The new feature {{array}} helper allows you create an array in a template. The working of this helper is similar to the already existing {{hash}} helper.
Five deprecations added in Ember.js 3.8 are -
Computed Property Overridability
Computed Property .property() Modifier
Computed Property Volatility
Deprecate @ember/object#aliasMethod
Component Manager Factory Function
Ember Data 3.8: No new features or deprecations are introduced in Ember Data 3.8, though there are a few fixes. Along with updating the documentation, the team has updated ‘_scheduleFetch’ to ‘use _fetchRecord’ for belongsTo relationship.
Ember CLI 3.8: The {{content-for}} hook has been updated to allow programmers to use it in the same way when different types are specified, for instance, {{content-for ‘head’}} {{content-for ‘head-footer’}}. With this release, gitignore will ignore Yarn .pnp files and the tests directory will be ignored when tests are turned off.
To learn more you can visit the announcing blog here.