update readme

Author: ananas-block

README.md

@@ -30,7 +30,27 @@ full compressed account lifecycle (create, increment, decrement, reset, close):
 
 - **[zk-id](./zk-id)** - A minimal zk id Solana program that uses zero-knowledge proofs for identity verification with compressed accounts.
 
-  
+## Tree Versions
+
+Compressed Accounts examples use different Tree versions:
+
+### V1 Trees (Mainnet)
+- **[counter/anchor](./counter/anchor/)** - Full compressed account lifecycle using Anchor
+- **[counter/native](./counter/native/)** - Full compressed account lifecycle using native Solana
+- **[counter/pinocchio](./counter/pinocchio/)** - Full compressed account lifecycle using Pinocchio
+- **[account-comparison](./account-comparison/)** - Account comparison example
+
+V1 Trees are deployed on **mainnet**.
+
+### V2 Trees (Local/Devnet)
+- **[create-and-update](./create-and-update/)** - Create and update accounts with single validity proof
+- **[read-only](./read-only)** - Create and read compressed accounts onchain
+- **[zk-id](./zk-id)** - Zero-knowledge identity verification
+
+V2 Trees consume **significantly less CU** (compute units) and are available on **local and devnet** environments.
+
+Both Tree versions are supported in Light SDK 0.16.0.
+
 ## Light Protocol dependencies
 
 ### Rust Crates