updated version of solidity to 0.8.10

contracts/FarmToken.sol

@@ -1,9 +1,12 @@
-pragma solidity ^0.6.2;
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity 0.8.10;
 
 import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import "@openzeppelin/contracts/utils/Address.sol";
-import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import "@openzeppelin/contracts/utils/math/SafeMath.sol";
+
 
 contract FarmToken is ERC20 {
     using Address for address;
@@ -12,10 +15,7 @@ contract FarmToken is ERC20 {
 
     IERC20 public token;
 
-    constructor(address _token)
-        public
-        ERC20("FarmToken", "FRM")
-    {
+    constructor(address _token) ERC20("FarmToken", "FRM") {
         token = IERC20(_token);
     }
 

contracts/MyToken.sol

@@ -1,9 +1,11 @@
-pragma solidity ^0.6.2;
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.2;
 
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 
 contract MyToken is ERC20 {
-    constructor() public ERC20("MyToken", "MTKN"){
+    constructor() ERC20("MyToken", "MTKN"){
         _mint(msg.sender, 1000000000000000000000000);
     }
+
 }

truffle-config.js

@@ -19,7 +19,6 @@
  */
 
 // const HDWalletProvider = require('@truffle/hdwallet-provider');
-// const infuraKey = "fj4jll3k.....";
 //
 // const fs = require('fs');
 // const mnemonic = fs.readFileSync(".secret").toString().trim();
@@ -54,7 +53,7 @@ module.exports = {
     // gas: 8500000,           // Gas sent with each transaction (default: ~6700000)
     // gasPrice: 20000000000,  // 20 gwei (in wei) (default: 100 gwei)
     // from: <address>,        // Account to send txs from (default: accounts[0])
-    // websockets: true        // Enable EventEmitter interface for web3 (default: false)
+    // websocket: true        // Enable EventEmitter interface for web3 (default: false)
     // },
     // Useful for deploying to a public network.
     // NB: It's important to wrap the provider as a function.
@@ -82,7 +81,9 @@ module.exports = {
   // Configure your compilers
   compilers: {
     solc: {
-      version: "0.6.2",    // Fetch exact version from solc-bin (default: truffle's version)
+      version: "0.8.10",
+        //version: "0.6.2",  
+      // version: "0.5.1",    // Fetch exact version from solc-bin (default: truffle's version)
       // docker: true,        // Use "0.5.1" you've installed locally with docker (default: false)
       // settings: {          // See the solidity docs for advice about optimization and evmVersion
       //  optimizer: {
@@ -92,5 +93,26 @@ module.exports = {
       //  evmVersion: "byzantium"
       // }
     }
-  }
+  },
+
+  // Truffle DB is currently disabled by default; to enable it, change enabled:
+  // false to enabled: true. The default storage location can also be
+  // overridden by specifying the adapter settings, as shown in the commented code below.
+  //
+  // NOTE: It is not possible to migrate your contracts to truffle DB and you should
+  // make a backup of your artifacts to a safe location before enabling this feature.
+  //
+  // After you backed up your artifacts you can utilize db by running migrate as follows: 
+  // $ truffle migrate --reset --compile-all
+  //
+  // db: {
+    // enabled: false,
+    // host: "127.0.0.1",
+    // adapter: {
+    //   name: "sqlite",
+    //   settings: {
+    //     directory: ".db"
+    //   }
+    // }
+  // }
 };