[unity] Upgrade of BlendModeMaterialAssets is performed for all Unity versions in spine-unity 4.0 an newer. See commit 752e72e, see #1822, see #1559.

CHANGELOG.md

@@ -84,6 +84,7 @@
     When exporting atlas textures from Spine with `Premultiply alpha` enabled (the default), you can leave it at `PMATexturePreset`. If you have disabled `Premultiply alpha`, set it to the included `StraightAlphaTexturePreset` asset. You can also create your own `TextureImporter` `Preset` asset and assign it here (include `PMA` or `Straight` in the name). In Unity versions before 2018.3 you can use `Texture2D` template assets instead of the newer `Preset` assets. Materials created for imported textures will also have the `Straight Alpha Texture` parameter configured accordingly.
   * All `Sprite` shaders (including URP and LWRP extension packages) now provide an additional `Fixed Normal Space` option `World-Space`. PReviously options were limited to `View-Space` and `Model-Space`.
   * `SkeletonGraphic` now fully supports [`SkeletonUtility`](http://esotericsoftware.com/spine-unity#SkeletonUtility) for generating a hierarchy of [`SkeletonUtilityBones`](http://esotericsoftware.com/spine-unity#SkeletonUtilityBone) in both modes `Follow` and `Override`. This also enables creating hinge chain physics rigs and using `SkeletonUtilityConstraints` such as `SkeletonUtilityGroundConstraint` and `SkeletonUtilityEyeConstraint` on `SkeletonGraphic`.
+  * Added **native support for slot blend modes** `Additive`, `Multiply` and `Screen` with automatic assignment at newly imported skeleton assets. `BlendModeMaterialAssets` are now obsolete and replaced by the native properties at `SkeletonDataAsset`. The `SkeletonDataAsset` Inspector provides a new `Blend Modes - Upgrade` button to upgrade an obsolete `BlendModeMaterialAsset` to the native blend modes properties. This upgrade will be performed automatically on imported and re-imported assets.
 
 * **Changes of default values**
 

spine-unity/Assets/Spine/Editor/spine-unity/Editor/Utility/BlendModeMaterialsUtility.cs

@@ -27,9 +27,8 @@
  * THE SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-#if UNITY_2020_1_OR_NEWER
+// from spine-unity 4.0 onward BlendModeMaterialAssets are obsolete and shall be upgraded.
 #define UPGRADE_ALL_BLEND_MODE_MATERIALS
-#endif
 
 using UnityEngine;
 using UnityEditor;