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title: Pebble SDK 4.0-dp1 - Changelog
date: 2016-06-15
---

This is the first Developer Preview release of the brand new Pebble SDK 4.0.
This changelog collects only changes visible to developers using the emulator.
A complete changelog will be provided when 4.0 ships on physical watches.

### Changes to Firmware

* Added support for [Pebble 2](https://www.kickstarter.com/projects/597507018/pebble-2-time-2-and-core-an-entirely-new-3g-ultra).
* Added [AppGlances](/guides/user-interfaces/appglance-c/) and Timeline 
~~Peek~~ Quick View.

### Changes to SDK

* Added the new "Diorite" platform for the Pebble 2.
* Added `PBL_COMPASS`, `PBL_SMARTSTRAP_POWER`, and `PBL_PLATFORM_DIORITE`
  defines.
* Added ``preferred_result_display_duration`` to get the recommended number of
  milliseconds a result window should be visible before it should closed.
* Added ``AppExitReason`` and ``exit_reason_set``
for an application to be able to notify the system of
[the reason it is exiting](/guides/user-interfaces/app-exit-reason/).
* Added ``AppGlanceSlice``, ``AppGlanceResult``, ``AppGlanceReloadSession``,
``app_glance_add_slice``, ``AppGlanceReloadCallback`` and ``app_glance_reload``.
to support [AppGlances](/guides/user-interfaces/appglance-c/).
* Added [Unobstructed Area APIs](/guides/user-interfaces/unobstructed-area/):
``UnobstructedAreaWillChangeHandler``,
``UnobstructedAreaChangeHandler``,
``UnobstructedAreaDidChangeHandler``,
``UnobstructedAreaHandlers``,
``layer_get_unobstructed_bounds``,
``unobstructed_area_service_subscribe``
and ``unobstructed_area_service_unsubscribe``
to enable a watchface to adapt to overlays partially obstructing it, such as
during a Timeline ~~Peek~~ Quick View.
* Added ``HealthMetricAlert``, ``HealthAggregation``, ``health_service_peek_current_value``,
  ``health_service_peek_current_value``, ``health_service_aggregate_averaged``,
  ``health_service_aggregate_averaged``,
  ``health_service_metric_aggregate_averaged_accessible``,
  ``health_service_register_metric_alert``,
  ``health_service_register_metric_alert`` and
  ``health_service_cancel_metric_alert`` in preparation for heart rate support.
  Note that these are not yet implemented.
* Report memory usage for Pebble Packages at build time.

### Changes to Documentation

* Added [AppGlances Guide](/guides/user-interfaces/appglance-c/)
* Added [Unobstructed Area Guide](/guides/user-interfaces/unobstructed-area/)
* Added [AppExitReason Guide](/guides/user-interfaces/app-exit-reason)
* Added [One Click Action Guide](/guides/design-and-interaction/one-click-actions/)
* Added API documentation for new ``HealthService``, ``App Glance``, ``UnobstructedArea`` and ``AppExitReason`` APIs.

### Known Issues

* Creating an ``AppGlanceSlice`` with a .expiration_time of
  `APP_GLANCE_SLICE_NO_EXPIRATION_TIME` results in an AppGlanceSlice that is
  never displayed.
* The ``UnobstructedAreaHandlers`` object must be created before being passed into
  the ``unobstructed_area_service_subscribe`` method.
* The Diorite emulator is still a little shy and will occassionally shake upon
  starting. If your emulator doesn't stop shaking, try installing an app - that
  usually brings it out of its shell.