v5.3/v6.1 What's new and upgrade guide (#1304)

docs/upgrade-guide.md

@@ -1,9 +1,27 @@
 # Upgrade Guide
 
+## Upgrading to v5.3/v6.1
+
+- `MapContext` is now an official API. The experimental `_MapContext` export will be removed in a future release.
+- `react-virtualized-auto-sizer` is no longer a dependency.
+- Inertia and smooth zooming has been enabled by default on the map controller. To revert to the behavior in previous versions, set the [interaction options](/docs/api-reference/interactive-map.md#interaction-options):
+
+```js
+const CONTROLLER_OPTS = {
+  dragPan: {inertia: 0},
+  dragRotate: {inertia: 0},
+  touchZoom: {inertia: 0},
+  scrollZoom: {smooth: false}
+};
+
+<MapGL {...CONTROLLER_OPTS} ... />
+```
+
 ## Upgrading to v6
 
 - A valid Mapbox access token is always required.
 - The default value of `InteractiveMap`'s `maxPitch` prop is changed to `85` from `60`.
+- `mapbox-gl` v2 introduced a breaking change to the build system. Transpiling it may result in a crash in the production build with the message `m is not defined`. Find solutions in [this thread](https://github.com/mapbox/mapbox-gl-js/issues/10173).
 
 ## Upgrading to v4
 

docs/whats-new.md

@@ -1,5 +1,21 @@
 # What's new
 
+## react-map-gl v5.3/v6.1
+
+Release date: Jan 27, 2020
+
+### Highlights
+
+- **TypeScript and Flow typings** are now published with the library
+- **More controller customizations.** Smooth easing on wheel scroll, three-finger gesture to change pitch, inertia after pan/pinch, and customizable keyboard navigation speed. See the updated [interaction options](/docs/api-reference/interactive-map.md#interaction-options) for details.
+- A new [eventRecognizerOptions](/docs/api-reference/interactive-map.md#eventrecognizeroptions) prop is added for fine-tuning the interaction experience.
+- New component: [AttributionControl](/docs/api-reference/attribution-control.md)
+- Promoted to official API: [MapContext](/docs/api-reference/map-context.md)
+- Resolved React error over attempted state update during render
+- `GeolocateControl` added supports for `showAccuracyCircle`
+- All controls now support inline styling with a `style` prop
+- All components and examples have been rewritten as functional components
+
 ## react-map-gl v6.0
 
 Release date: Dec 16, 2020