diff --git a/README.md b/README.md
index 169fcdf..8cc3fcd 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,11 @@ soldeer install noble-std
 
 <pre>
 src
-└── <a href="./src/ConsensusInfo.sol">ConsensusInfo.sol</a>: A library for interacting with Noble's ConsensusInfo system contract.
+├── <a href="./src/ConsensusInfo.sol">ConsensusInfo.sol</a>: A library for interacting with Noble's ConsensusInfo system contract.
+├── <a href="./src/Constants.sol">Constants.sol</a>: Noble specific constants (system address, contract addresses).
+└── interfaces
+    ├── <a href="./src/interfaces/IRegistrar.sol">IRegistrar.sol</a>: Interface for the Registrar contract.
+    └── <a href="./src/interfaces/IValidatorManager.sol">IValidatorManager.sol</a>: Interface for the Validator Manager contract.
 </pre>
 
 ## Support
diff --git a/src/Constants.sol b/src/Constants.sol
index 75b6069..55657bf 100644
--- a/src/Constants.sol
+++ b/src/Constants.sol
@@ -4,5 +4,14 @@ pragma solidity >=0.8.13 <0.9.0;
 /// @dev The address of the system account on Noble.
 address constant SYSTEM_ADDRESS = 0xffffFFFfFFffffffffffffffFfFFFfffFFFfFFfE;
 
+/// @dev The address of the Noble (ERC20) predeployed contract on Noble.
+address constant TOKEN_ADDRESS = 0x6625300000000000000000000000000000000000;
+
 /// @dev The address of the ConsensusInfo system contract on Noble.
 address constant CONSENSUS_INFO_ADDRESS = 0x6625300000000000000000000000000000000001;
+
+/// @dev The address of the ValidatorManager predeployed contract on Noble.
+address constant VALIDATOR_MANAGER_ADDRESS = 0x6625300000000000000000000000000000000002;
+
+/// @dev The address of the Registrar predeployed contract on Noble.
+address constant REGISTRAR_ADDRESS = 0x6625300000000000000000000000000000000003;
diff --git a/src/interfaces/IRegistrar.sol b/src/interfaces/IRegistrar.sol
index 8c3557e..a920caa 100644
--- a/src/interfaces/IRegistrar.sol
+++ b/src/interfaces/IRegistrar.sol
@@ -1,5 +1,5 @@
-// SPDX-License-Identifier: Apache-2.0
-pragma solidity >=0.8.0 <0.9.0;
+// SPDX-License-Identifier: MIT OR Apache-2.0
+pragma solidity >=0.8.13 <0.9.0;
 
 /// @title IRegistrar
 /// @notice Interface for the Registrar contract.
diff --git a/src/interfaces/IValidatorManager.sol b/src/interfaces/IValidatorManager.sol
index a2ad491..21770b0 100644
--- a/src/interfaces/IValidatorManager.sol
+++ b/src/interfaces/IValidatorManager.sol
@@ -1,5 +1,5 @@
-// SPDX-License-Identifier: Apache-2.0
-pragma solidity >=0.8.0 <0.9.0;
+// SPDX-License-Identifier: MIT OR Apache-2.0
+pragma solidity >=0.8.13 <0.9.0;
 
 /// @title IValidatorManager
 /// @notice Interface for the Validator Manager contract.