diff --git a/solidity/src/CadenceArchUtils.sol b/solidity/src/CadenceArchUtils.sol
index 35e92a6..c43b6bd 100644
--- a/solidity/src/CadenceArchUtils.sol
+++ b/solidity/src/CadenceArchUtils.sol
@@ -1,5 +1,5 @@
-// SPDX-License-Identifier: MIT
-pragma solidity 0.8.19;
+// SPDX-License-Identifier: Unlicense
+pragma solidity ^0.8.19;
 
 /**
  * @dev This contract is a base contract to facilitate easier consumption of the Cadence Arch pre-compiles. Implementing
diff --git a/solidity/src/CadenceRandomConsumer.sol b/solidity/src/CadenceRandomConsumer.sol
index a8d11a8..439a573 100644
--- a/solidity/src/CadenceRandomConsumer.sol
+++ b/solidity/src/CadenceRandomConsumer.sol
@@ -1,5 +1,5 @@
-// SPDX-License-Identifier: MIT
-pragma solidity 0.8.19;
+// SPDX-License-Identifier: Unlicense
+pragma solidity ^0.8.19;
 
 import {CadenceArchUtils} from "./CadenceArchUtils.sol";
 import {Xorshift128plus} from "./Xorshift128plus.sol";
diff --git a/solidity/src/CoinToss.sol b/solidity/src/CoinToss.sol
index 148af9b..10a533b 100644
--- a/solidity/src/CoinToss.sol
+++ b/solidity/src/CoinToss.sol
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: Unlicense
 pragma solidity 0.8.19;
 
 import {CadenceRandomConsumer} from "./CadenceRandomConsumer.sol";
diff --git a/solidity/src/Xorshift128plus.sol b/solidity/src/Xorshift128plus.sol
index d62026b..0e65221 100644
--- a/solidity/src/Xorshift128plus.sol
+++ b/solidity/src/Xorshift128plus.sol
@@ -1,5 +1,5 @@
-// SPDX-License-Identifier: MIT
-pragma solidity 0.8.19;
+// SPDX-License-Identifier: Unlicense
+pragma solidity ^0.8.19;
 
 /**
  * @dev This library implements the Xorshift128+ pseudo-random number generator (PRG) algorithm.
diff --git a/solidity/src/test/TestCadenceRandomConsumer.sol b/solidity/src/test/TestCadenceRandomConsumer.sol
index 328ec5b..4af8e86 100644
--- a/solidity/src/test/TestCadenceRandomConsumer.sol
+++ b/solidity/src/test/TestCadenceRandomConsumer.sol
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: Unlicense
 pragma solidity 0.8.19;
 
 import {CadenceRandomConsumer} from "../CadenceRandomConsumer.sol";
diff --git a/solidity/test/CadenceRandomConsumer.t.sol b/solidity/test/CadenceRandomConsumer.t.sol
index faf8fa3..ad41056 100644
--- a/solidity/test/CadenceRandomConsumer.t.sol
+++ b/solidity/test/CadenceRandomConsumer.t.sol
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: Unlicense
 pragma solidity 0.8.19;
 
 import "forge-std/Test.sol";
diff --git a/solidity/test/CoinToss.t.sol b/solidity/test/CoinToss.t.sol
index 580dbd6..bad9153 100644
--- a/solidity/test/CoinToss.t.sol
+++ b/solidity/test/CoinToss.t.sol
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: Unlicense
 pragma solidity 0.8.19;
 
 import "forge-std/Test.sol";