diff --git a/docs/reference/software-versions.mdx b/docs/reference/software-versions.mdx
index 0b73f3373..a0777daa1 100644
--- a/docs/reference/software-versions.mdx
+++ b/docs/reference/software-versions.mdx
@@ -4,8 +4,6 @@ title: Software Versions
 description: Soroban software releases and changelogs.
 ---
 
-We're releasing early versions of Soroban because we believe it's important to share the development process, and we want Stellar ecosystem developers and smart contract developers from other ecosystems to have a chance to experiment and provide feedback.
-
 :::caution
 
 Release candidates are software releases that are also released to the [Testnet] test network. Software releases may occur between Testnet releases. If you're interacting with Testnet, the recommended software versions to use in development are provided below. Releases to Testnet may include network resets and network passphrase changes.
@@ -14,6 +12,50 @@ Release candidates are software releases that are also released to the [Testnet]
 
 [testnet]: ./networks.mdx
 
+## Protocol 21 (Mainnet, June 18, 2024)
+
+### Software
+
+| Software | Version |
+| --- | --- |
+| XDR | `v21.1` |
+| Rust XDR | `v21.0.1` |
+| Soroban Environment | `v21.0.2` |
+| Stellar Core | `v21.0.0` |
+| Soroban Rust SDK | `21.0.1-preview.3` |
+| Soroban CLI | `v21.0.0-rc.1` |
+| Soroban RPC | `v21.2.0` |
+| Stellar Horizon | `v2.30.0` |
+| Stellar Quickstart | `https://hub.docker.com/layers/stellar/quickstart/v426-latest-amd64/images/sha256-274395daab6fa8033b9213f152d56699358917fb01d7c7e95392a37fc00c9d01` |
+| Stellar JS Stellar Base | `v12.0.0-rc1` |
+| Stellar JS Stellar SDK | `v12.0.0-rc.3` |
+| Freighter |  |
+| Laboratory |  |
+| Soroban React Payment dapp | `TBD` |
+| Soroban Mint Token dapp | `TBD` |
+| Soroban Swap Token dapp | `TBD` |
+| Futurenet Network Passphrase | `Test SDF Future Network ; October 2022` |
+| Testnet Network Passphrase | `Test SDF Network ; September 2015` |
+| Mainnet Network Passphrase | `Public Global Stellar Network ; September 2015` |
+
+### Release notes
+
+#### Core
+
+New features in Protocol 21:
+
+- Secp256r1 support in Soroban host: https://github.com/stellar/stellar-protocol/blob/master/core/cap-0051.md
+- Soroban host function for extending TTL of contract instance and code separately: https://github.com/stellar/stellar-protocol/blob/master/core/cap-0053.md
+- Use refined cost model for VM instantiation in order to reduce the VM instantiation metered costs: https://github.com/stellar/stellar-protocol/blob/master/core/cap-0054.md
+- Intra-transaction VM module caching for the further Soroban cost reduction: https://github.com/stellar/stellar-protocol/blob/master/core/cap-0055.md, https://github.com/stellar/stellar-protocol/blob/master/core/cap-0056.md
+
+#### Soroban Rust SDK
+
+Key protocol-related changes:
+
+- Support for secp256r1 signature verification
+- Support for extending TTL of contract instance and code separate from each other
+
 ## Protocol 21 (Testnet only, May 20, 2024)
 
 ### Software