When a new version for a browser is shipped, it comes with all the latest features of ECMAScript packed inside it. This has a very significant impact on web development as developers can start using the latest standards to ease the process and write more fluid and performant code. But it is not always possible, using these new features means leaving behind the users who are still using the old browser, posing a dilemma for developers.
Well, Meteor 1.7 brings the best of both worlds by automatically building two sets of client-side assets, one tailored to the capabilities of the modern browser, and the other designed to work equally well on all supported browsers. This will help legacy browsers continue to work exactly the same as they were before.
The npm packages are precompiled before they are published, so users of these packages have to settle for the compilation strategy decided by the author. Meteor 1.7, allows you to control how an npm package is compiled, or compile the package for modern/legacy browsers and Node. This lets application developers take complete control of the npm modules they are using.
Most of the new features in Meteor 1.7 can be applied in a backward compatible manner or they can be opted out, it is completely a developer’s choice. For a complete breakdown of the new Meteor features, refer to this Official Meteor blog page.