Microsoft had already clarified about Extensions in Microsoft Edge will be available in future updates of Windows 10. According to sources, Microsoft is finally ready to begin to introduce extension support for Edge in an upcoming Insider release preview build. Extensions in Microsoft Edge are now available in the latest internal rs1_release builds. Build 14284 is assumed to be the first rs1_release build that will include extensions in Edge. Current Insider build is very close to this build number and the Insider fast being really fast nowadays means they are coming this week or next week.
Extensions for Microsoft Edge are scheduled to launch officially with Redstone 1 update in June. Developers will get around three months to port and test their own extensions before extensions are rolled out to the public. It is one of the most requested features currently submitted via the feedback app. We will learn more about extensions during the upcoming BUILD developer conference in San Francisco. Microsoft will definitely detail how developers can get their extensions and apps ported over from Chrome to Edge.