[wip] Docs for Unity SDK V4.0.0

docs/unity.md

@@ -2,26 +2,38 @@
 title: Tezos Unity SDK
 authors: Tim McMackin
 last_update:
-  date: 11 January 2024
+  date: 25 November 2024
 ---
 
-The Tezos Unity SDK provides tools that let you access user wallets and Tezos in games and other Unity projects.
-You can use Tezos via the SDK to:
+The Tezos Unity SDK provides tools that let you access user wallets and blockchains in games and other Unity projects.
+You can use the SDK to:
 
-- Use a player's Tezos account as their account for a game and their wallet as their way of logging in to the game
-- Accept payments from players in tez
-- Use Tezos to create game assets, store player inventories, and transfer assets between players
-- Verify that users own specific game assets and allow them to sell or share them to other players
-- Use Tezos smart contracts as backend logic for games
+- Use a player's account as their account for a game and their wallet as their way of logging in to the game
+- Accept payments from players in tez (XTZ), the primary cryptocurrency of the Tezos and Etherlink blockchains
+- Use blockchains to create game assets, store player inventories, and transfer assets between players
+- Verify that users own specific game assets and allow them to transfer them to other players
+- Use smart contracts as backend logic for games
+
+The SDK can connect to and use these blockchains:
+
+- [Tezos](https://tezos.com)
+- [Etherlink](https://etherlink.com)
 
 ## Installation and use
 
 For a walkthrough of installing and using the SDK in an existing Unity project, see [Quickstart](/unity/quickstart).
 
+## Upgrading from version 3
+
+Version 4.0 has breaking changes.
+To upgrade, see [Upgrading the Unity SDK](/unity/upgrading).
+
+<!--
 ## Tutorial scenes
 
 The SDK includes tutorial scenes that demonstrate how to use the SDK.
 For information about setting up and using the scenes, see [Tutorial scenes](/unity/scenes).
+-->
 
 ## Sample game
 
@@ -38,9 +50,13 @@ The Tezos SDK uses modified versions of the following libraries for communicatio
 
 - **Airgap Beacon SDK**: Interacts with Tezos wallets through the Beacon standard for iOS, Android, and WebGL platforms.
 - **Netezos**: Interacts with Tezos wallets through the Beacon standard for Windows, Linux, and MacOS platforms. Also prepares parameters for smart contract calls and interprets complex data returned by the ReadView method.
+- **WalletConnect**: Interacts with EVM wallets with the WalletConnect protocol.
+To use WalletConnect wallets, you must install the [Tezos WalletConnect Unity SDK](https://github.com/trilitech/tezos-wallet-connect-unity-sdk).
 
 The SDK also uses the [Newtonsoft JSON Unity Package](https://docs.unity3d.com/Packages/[email protected]/manual/index.html).
 
 ## Supported Platforms
 
 The SDK supports Windows, Linux, MacOS, iOS, Android, and WebGL platforms.
+
+For information about the kinds of wallets the SDK supports, see [Connecting accounts](/unity/connecting-accounts).