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title: Pebble SDK 4.2 - Changelog
date: 2016-10-18
---

### Changes to Firmware

* Emery can now run apps compiled for Basalt (SDK 4.1 or earlier) or Aplite
  (SDK 3.7 or earlier) in "bezel mode".
* Fixed ``health_service_metric_accessible`` for heartrate-related metrics.
  * Note that, as heartrate data is only retained for two hours, HRM accessibility
    checks going back further than two hours will always return `false`.
* Rocky.js: The reliability of the ``postMessage`` API has been improved.
* Rocky.js: `postmessageconnected`, `postmessagedisconnected` and `postmessageerror`
  events have been added.
* Rocky.js: Using regular expressions no longer results in substantial app log spam.
* Rocky.js: The coordinate system was adjusted by 0.5 pixels; (0, 0) now refers to
  top left of the first pixel, rather than the center of the pixel.
* Rocky.js: The `memorypressure` event has been added. When fired with
  `{level: 'high'}`, the app must free up sufficient memory or it will be
  terminated.
* Rocky.js: Content size is exposed via ``UserPreferences``.
* Rocky.js: `watchInfo.platform` now works as expected in the emulator.
* Rocky.js: Removed the global `print()` function; use `console.log()`.
* Rocky.js: Fixed a crash when passing invalid values to `clearTimeout` or
  `clearInterval`.
* Rocky.js: Provided constructors for `CanvasRenderingContext2D`, `RockyCanvasElement`
  and `Event`.
* Rocky.js: Removed unimplemented methods that previously threw an exception when called,
  allowing for polyfills of those methods.
* Rocky.js: Added the ability to unsubscribe from events using ``removeEventListener`` or
  ``off``.
* Bug fixes and improvements.


### Changes to SDK

* Added support for the Emery platform.
* Rocky.js is now considered stable, and can be used to submit apps to the appstore.
* Rocky.js: The default app template has been improved.
* Added ``preferred_content_size()`` to retrieve the user's preferred font size.
* All JS bundling is now performed using [webpack](https://webpack.github.io)
  * Only JavaScript files that are actually used are now bundled.