diff --git a/s/Solidity.sol b/s/Solidity.sol
index f331e579..af4f89c4 100644
--- a/s/Solidity.sol
+++ b/s/Solidity.sol
@@ -1,7 +1,7 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.6.4;
 
 contract HelloWorld {
-    function render () public pure returns (string) {
+    function render () public pure returns (string memory) {
         return 'Hello World';
     }
 }