[ios][android] Add change log entry

platform/android/CHANGELOG.md

@@ -7,6 +7,9 @@ Mapbox welcomes participation and contributions from everyone.  If you'd like to
  - Introduce `clusterProperties` option for aggregated cluster properties. [#15425](https://github.com/mapbox/mapbox-gl-native/pull/15425)
  - Expose the `CameraPosition#padding` field and associated utility camera position builders. This gives a choice to set a persisting map padding immediately during a transition instead of setting it lazily `MapboxMap#setPadding`, which required scheduling additional transition to be applied. This also deprecates `MapboxMap#setPadding` as there should be no need for a lazy padding setter. [#15444](https://github.com/mapbox/mapbox-gl-native/pull/15444)
 
+ ### Performance improvements
+ - Mark used offline region resources in batches. [#15521](https://github.com/mapbox/mapbox-gl-native/pull/15521)
+
 ## 8.3.0 - August 28, 2019
 [Changes](https://github.com/mapbox/mapbox-gl-native/compare/android-v8.3.0-beta.1...android-v8.3.0) since [Mapbox Maps SDK for Android v8.3.0-beta.1](https://github.com/mapbox/mapbox-gl-native/releases/tag/android-v8.3.0-beta.1):
 

platform/ios/CHANGELOG.md

@@ -7,6 +7,10 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 * Fixed an issue that caused the tilt gesture to trigger too easily and conflict with pinch or pan gestures. ([#15349](https://github.com/mapbox/mapbox-gl-native/pull/15349))
 * Fixed a bug with annotation view positions after camera transitions. ([#15122](https://github.com/mapbox/mapbox-gl-native/pull/15122/))
 
+ ### Performance improvements
+
+ * Mark used offline region resources in batches. ([#15521](https://github.com/mapbox/mapbox-gl-native/pull/15521))
+
 ## 5.3.0 - August 28, 2019
 
 This release changes how offline tile requests are billed — they are now billed on a pay-as-you-go basis and all developers are able raise the offline tile limit for their users. Offline requests were previously exempt from monthly active user (MAU) billing and increasing the offline per-user tile limit to more than 6,000 tiles required the purchase of an enterprise license. By upgrading to this release, you are opting into the changes outlined in [this blog post](https://blog.mapbox.com/offline-maps-for-all-bb0fc51827be) and [#15380](https://github.com/mapbox/mapbox-gl-native/pull/15380).