updated readme

Author: GieziJo

README.md

@@ -4,6 +4,18 @@
 [![twitter](https://img.shields.io/twitter/follow/JoGiezi?style=social)](https://twitter.com/JoGiezi)
 
 # Scriptable Object Variant for Unity (Scriptable Object Data Overrider)
+
+> [!CAUTION]
+> If you are upgrading from a pre-`2.0.0` version, please read the [upgrade section](#upgrading-to-200-from-previous-versions)
+
+## Table of contents
+- [Description](#description)
+- [Usage](#usage)
+- [Implementation](#implementation)
+- [Installation](#installation)
+- [Upgrading to 2.0.0 from previous versions](#upgrading-to-200-from-previous-versions)
+- [Known issues and tweaks to be made](#known-issues-and-tweaks-to-be-made)
+
 ## Description
 Adds a field to any scriptable object tagged with the `[SOVariant]` attribute that lets you select an original SO (parent) and override selected fields in the child object.
 
@@ -87,10 +99,19 @@ SOVariantHelper<ScriptableObject>.SetParentOverrideValues(target, parent, new Di
 
 ## Implementation
 The visual interface is implemented in [Odin](odininspector.com/)'s [`OdinPropertyProcessor`](https://odininspector.com/tutorials/using-property-resolvers-and-attribute-processors/custom-property-processors).
-The data with the parent and the overriden fields is kept serialized inside the asset's metadata, set in unity with `AssetImporter.GetAtPath(AssetDatabase.GetAssetPath(targetObject)).userData`.
+
+The data with the parent and the overriden fields is kept in a library object located at `Assets/Plugins/SOVariant/Editor/SOVariantDataLibrary.asset`
+
+<p style="color: grey";>Before 2.0.0:
+<strike>The data with the parent and the overriden fields is kept serialized inside the asset's metadata, set in unity with `AssetImporter.GetAtPath(AssetDatabase.GetAssetPath(targetObject)).userData`.</strike></p>
 
 ## Installation
-> Requires [Odin](odininspector.com/) to be installed before adding the package
+> [!WARNING]
+> Requires [Odin](odininspector.com/) version `3.2.1.0` to be installed before adding the package.
+
+> [!WARNING]
+> This package is maintained for Unity version 2022.3.16f1 LTS.
+
 ### Using Unity's package manager
 Add the line
 ```
@@ -109,6 +130,21 @@ the package will be added as a scoped registry, which you can inspect under `Pro
 ### Alternative
 Download and copy all files inside your project.
 
+## Upgrading to 2.0.0 from previous versions
+
+In version `2.0.0` of the package, the data moved from within each object's metadata to using a Scriptable Object library.
+Unity's importer being too unstable, reading and writing the data to the metadata became too complicated and often led to errors and failures.
+
+If you were using the package pre-`2.0.0`, a tool has been written to migrate to the new version.
+Run `Tools/GieziTools/SOVariant/Upgrade user data to new version`.
+This will read all data contained in the metadata and build the library.
+If necessary, you can run `Tools/GieziTools/SOVariant/Fix SOVs`.
+This will loop through each object and rebuild the parent/child relationship, as well as propagate the parent values to the children.
+Because the previous version of the tool was quite unstable, this step is highly encouraged
+Additionally, you should check the data to make sure each object has the right values.
+
+This new version should fix a lot of the issues that appeared with newer versions of Unity and with the package being unstable.
+
 ## Known issues and tweaks to be made
 <details>
 <summary>List of known issues</summary>