updated version

contracts/EncryptedERC20.sol

@@ -104,14 +104,14 @@ contract EncryptedERC20 is EIP712WithModifier {
 
     function _updateAllowance(address owner, address spender, euint32 amount) internal {
         euint32 currentAllowance = _allowance(owner, spender);
-        TFHE.req(TFHE.le(amount, currentAllowance));
+        TFHE.optReq(TFHE.le(amount, currentAllowance));
         _approve(owner, spender, TFHE.sub(currentAllowance, amount));
     }
 
     // Transfers an encrypted amount.
     function _transfer(address from, address to, euint32 amount) internal {
         // Make sure the sender has enough tokens.
-        TFHE.req(TFHE.le(amount, balances[from]));
+        TFHE.optReq(TFHE.le(amount, balances[from]));
 
         // Add to the balance of `to` and subract from the balance of `from`.
         balances[to] = TFHE.add(balances[to], amount);

hardhat.config.ts

@@ -123,7 +123,7 @@ const config: HardhatUserConfig = {
     tests: "./test",
   },
   solidity: {
-    version: "0.8.17",
+    version: "0.8.19",
     settings: {
       metadata: {
         // Not including the metadata hash

package.json

@@ -27,8 +27,8 @@
     "eslint": "^8.28.0",
     "eslint-config-prettier": "^8.5.0",
     "ethers": "^6.4.0",
-    "fhevm": "^0.1.6",
-    "fhevmjs": "^0.1.3",
+    "fhevm": "^0.1.13",
+    "fhevmjs": "^0.2.1",
     "fs-extra": "^10.1.0",
     "hardhat": "^2.12.2",
     "hardhat-deploy": "^0.11.29",