Add upgrade notes

Author: mattamon

doc/01_Installation/02_Upgrade.md

@@ -6,3 +6,24 @@ Following steps are necessary during updating to newer versions.
 - Execute the following command to reindex all elements to be able to use all new features:
 
   ```bin/console generic-data-index:update:index```
+
+## Upgrade to 2.0.0
+
+### BC-Breaks
+
+#### Interface changes
+-  Added `PermissionTypes $permissionType` parameter with default type `PermissionTypes::LIST` to
+- `AssetSearchServiceInterface::search` method
+- `DocumentSearchServiceInterface::search` method
+- `DataObjectSearchServiceInterface::search` method
+- `ElementSearchServiceInterface::search` method
+- Search services `byId` methods now return elements based on the `PermissionTypes::VIEW` permission
+- Added type specific interfaces for searches to avoid mixing up different search types in search services
+  - `AssetSearch` now implements `AssetSearchInterface`
+  - `DocumentSearch` now implements `DocumentSearchInterface`
+  - `ElementSearch` now implements `ElementSearchInterface`
+- Search services now require the specific search type for the search
+  - `AssetSearchServiceInterface::search` now requires a `AssetSearchInterface`
+  - `DocumentSearchServiceInterface::search`  now requires a `DocumentSearchInterface`
+  - `ElementSearchServiceInterface::search`  now requires a `ElementSearchInterface`
+- `SearchProviderInterface` now returns type specific search interfaces