diff --git a/contracts/contracts/MACI.sol b/contracts/contracts/MACI.sol
index bd9b2f7b6b..8bed750c89 100644
--- a/contracts/contracts/MACI.sol
+++ b/contracts/contracts/MACI.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { IPollFactory } from "./interfaces/IPollFactory.sol";
 import { IMessageProcessorFactory } from "./interfaces/IMPFactory.sol";
@@ -17,7 +17,7 @@ import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
 
 /// @title MACI - Minimum Anti-Collusion Infrastructure Version 1
 /// @notice A contract which allows users to sign up, and deploy new polls
-contract MACI is IMACI, DomainObjs, Params, Utilities, Ownable {
+contract MACI is IMACI, DomainObjs, Params, Utilities, Ownable(msg.sender) {
   /// @notice The state tree depth is fixed. As such it should be as large as feasible
   /// so that there can be as many users as possible.  i.e. 5 ** 10 = 9765625
   /// this should also match the parameter of the circom circuits.
diff --git a/contracts/contracts/MessageProcessor.sol b/contracts/contracts/MessageProcessor.sol
index de411a246c..866ef9f634 100644
--- a/contracts/contracts/MessageProcessor.sol
+++ b/contracts/contracts/MessageProcessor.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { AccQueue } from "./trees/AccQueue.sol";
 import { IMACI } from "./interfaces/IMACI.sol";
@@ -17,7 +17,7 @@ import { DomainObjs } from "./utilities/DomainObjs.sol";
 /// @dev MessageProcessor is used to process messages published by signup users.
 /// It will process message by batch due to large size of messages.
 /// After it finishes processing, the sbCommitment will be used for Tally and Subsidy contracts.
-contract MessageProcessor is Ownable, SnarkCommon, Hasher, CommonUtilities, IMessageProcessor, DomainObjs {
+contract MessageProcessor is Ownable(msg.sender), SnarkCommon, Hasher, CommonUtilities, IMessageProcessor, DomainObjs {
   /// @notice custom errors
   error NoMoreMessages();
   error StateAqNotMerged();
diff --git a/contracts/contracts/Poll.sol b/contracts/contracts/Poll.sol
index 9bc9184bb4..4480bd2701 100644
--- a/contracts/contracts/Poll.sol
+++ b/contracts/contracts/Poll.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { Params } from "./utilities/Params.sol";
 import { SnarkCommon } from "./crypto/SnarkCommon.sol";
@@ -15,7 +15,7 @@ import { Utilities } from "./utilities/Utilities.sol";
 /// which can be either votes, key change messages or topup messages.
 /// @dev Do not deploy this directly. Use PollFactory.deploy() which performs some
 /// checks on the Poll constructor arguments.
-contract Poll is Params, Utilities, SnarkCommon, Ownable, EmptyBallotRoots, IPoll {
+contract Poll is Params, Utilities, SnarkCommon, Ownable(msg.sender), EmptyBallotRoots, IPoll {
   using SafeERC20 for ERC20;
 
   /// @notice Whether the Poll has been initialized
diff --git a/contracts/contracts/PollFactory.sol b/contracts/contracts/PollFactory.sol
index ae62a1b761..5cff4bd914 100644
--- a/contracts/contracts/PollFactory.sol
+++ b/contracts/contracts/PollFactory.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { IMACI } from "./interfaces/IMACI.sol";
 import { AccQueue } from "./trees/AccQueue.sol";
diff --git a/contracts/contracts/SignUpToken.sol b/contracts/contracts/SignUpToken.sol
index 759a719d13..e069c06004 100644
--- a/contracts/contracts/SignUpToken.sol
+++ b/contracts/contracts/SignUpToken.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { ERC721 } from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
 import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
@@ -7,7 +7,7 @@ import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
 /// @title SignUpToken
 /// @notice This contract is an ERC721 token contract which
 /// can be used to allow users to sign up for a poll.
-contract SignUpToken is ERC721, Ownable {
+contract SignUpToken is ERC721, Ownable(msg.sender) {
   /// @notice The constructor which calls the ERC721 constructor
   constructor() payable ERC721("SignUpToken", "SignUpToken") {}
 
diff --git a/contracts/contracts/Tally.sol b/contracts/contracts/Tally.sol
index 3ae0165cb5..6929436400 100644
--- a/contracts/contracts/Tally.sol
+++ b/contracts/contracts/Tally.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { IMACI } from "./interfaces/IMACI.sol";
 import { Hasher } from "./crypto/Hasher.sol";
@@ -15,7 +15,7 @@ import { DomainObjs } from "./utilities/DomainObjs.sol";
 /// @title Tally
 /// @notice The Tally contract is used during votes tallying
 /// and by users to verify the tally results.
-contract Tally is Ownable, SnarkCommon, CommonUtilities, Hasher, DomainObjs {
+contract Tally is Ownable(msg.sender), SnarkCommon, CommonUtilities, Hasher, DomainObjs {
   uint256 internal constant TREE_ARITY = 5;
 
   /// @notice The commitment to the tally results. Its initial value is 0, but after
diff --git a/contracts/contracts/TopupCredit.sol b/contracts/contracts/TopupCredit.sol
index e3c09f71a8..9a13ebe938 100644
--- a/contracts/contracts/TopupCredit.sol
+++ b/contracts/contracts/TopupCredit.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
@@ -7,7 +7,7 @@ import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
 /// @title TopupCredit
 /// @notice A contract representing a token used to topup a MACI's voter
 /// credits
-contract TopupCredit is ERC20, Ownable {
+contract TopupCredit is ERC20, Ownable(msg.sender) {
   uint8 public constant DECIMALS = 1;
   uint256 public constant MAXIMUM_AIRDROP_AMOUNT = 100000 * 10 ** DECIMALS;
 
diff --git a/contracts/contracts/VkRegistry.sol b/contracts/contracts/VkRegistry.sol
index 2298d34f89..f0b26d9e78 100644
--- a/contracts/contracts/VkRegistry.sol
+++ b/contracts/contracts/VkRegistry.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { SnarkCommon } from "./crypto/SnarkCommon.sol";
 import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
@@ -10,7 +10,7 @@ import { DomainObjs } from "./utilities/DomainObjs.sol";
 /// @notice Stores verifying keys for the circuits.
 /// Each circuit has a signature which is its compile-time constants represented
 /// as a uint256.
-contract VkRegistry is Ownable, DomainObjs, SnarkCommon, IVkRegistry {
+contract VkRegistry is Ownable(msg.sender), DomainObjs, SnarkCommon, IVkRegistry {
   mapping(Mode => mapping(uint256 => VerifyingKey)) internal processVks;
   mapping(Mode => mapping(uint256 => bool)) internal processVkSet;
 
diff --git a/contracts/contracts/benchmarks/HasherBenchmarks.sol b/contracts/contracts/benchmarks/HasherBenchmarks.sol
index 27327ef87e..4a99af88a1 100644
--- a/contracts/contracts/benchmarks/HasherBenchmarks.sol
+++ b/contracts/contracts/benchmarks/HasherBenchmarks.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { Hasher } from "../crypto/Hasher.sol";
 
diff --git a/contracts/contracts/crypto/Hasher.sol b/contracts/contracts/crypto/Hasher.sol
index d332a8bcc0..9445bd6da6 100644
--- a/contracts/contracts/crypto/Hasher.sol
+++ b/contracts/contracts/crypto/Hasher.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { SnarkConstants } from "./SnarkConstants.sol";
 import { PoseidonT3 } from "./PoseidonT3.sol";
diff --git a/contracts/contracts/crypto/MockVerifier.sol b/contracts/contracts/crypto/MockVerifier.sol
index d9a8b00edc..2b8507a023 100644
--- a/contracts/contracts/crypto/MockVerifier.sol
+++ b/contracts/contracts/crypto/MockVerifier.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { SnarkConstants } from "./SnarkConstants.sol";
 import { SnarkCommon } from "./SnarkCommon.sol";
diff --git a/contracts/contracts/crypto/Pairing.sol b/contracts/contracts/crypto/Pairing.sol
index 9239d19519..4c65e101ac 100644
--- a/contracts/contracts/crypto/Pairing.sol
+++ b/contracts/contracts/crypto/Pairing.sol
@@ -18,7 +18,7 @@
 
 // 2019 OKIMS
 
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 /// @title Pairing
 /// @notice A library implementing the alt_bn128 elliptic curve operations.
diff --git a/contracts/contracts/crypto/PoseidonT3.sol b/contracts/contracts/crypto/PoseidonT3.sol
index c9825d32de..be8d47e060 100644
--- a/contracts/contracts/crypto/PoseidonT3.sol
+++ b/contracts/contracts/crypto/PoseidonT3.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 /// @notice A library which provides functions for computing Pedersen hashes.
 library PoseidonT3 {
diff --git a/contracts/contracts/crypto/PoseidonT4.sol b/contracts/contracts/crypto/PoseidonT4.sol
index 615c955f9e..2187bc8333 100644
--- a/contracts/contracts/crypto/PoseidonT4.sol
+++ b/contracts/contracts/crypto/PoseidonT4.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 /// @notice A library which provides functions for computing Pedersen hashes.
 library PoseidonT4 {
diff --git a/contracts/contracts/crypto/PoseidonT5.sol b/contracts/contracts/crypto/PoseidonT5.sol
index 46bb22e028..af57b2f314 100644
--- a/contracts/contracts/crypto/PoseidonT5.sol
+++ b/contracts/contracts/crypto/PoseidonT5.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 /// @notice A library which provides functions for computing Pedersen hashes.
 library PoseidonT5 {
diff --git a/contracts/contracts/crypto/PoseidonT6.sol b/contracts/contracts/crypto/PoseidonT6.sol
index 1f677da10d..820613be67 100644
--- a/contracts/contracts/crypto/PoseidonT6.sol
+++ b/contracts/contracts/crypto/PoseidonT6.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 /// @notice A library which provides functions for computing Pedersen hashes.
 library PoseidonT6 {
diff --git a/contracts/contracts/crypto/SnarkCommon.sol b/contracts/contracts/crypto/SnarkCommon.sol
index e63bd8ec5f..acdd65e1bf 100644
--- a/contracts/contracts/crypto/SnarkCommon.sol
+++ b/contracts/contracts/crypto/SnarkCommon.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 import { Pairing } from "./Pairing.sol";
 
 /// @title SnarkCommon
diff --git a/contracts/contracts/crypto/SnarkConstants.sol b/contracts/contracts/crypto/SnarkConstants.sol
index e263121fce..dd0075b680 100644
--- a/contracts/contracts/crypto/SnarkConstants.sol
+++ b/contracts/contracts/crypto/SnarkConstants.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 /// @title SnarkConstants
 /// @notice This contract contains constants related to the SNARK
diff --git a/contracts/contracts/crypto/Verifier.sol b/contracts/contracts/crypto/Verifier.sol
index 7654fe6bb0..68363e7e2b 100644
--- a/contracts/contracts/crypto/Verifier.sol
+++ b/contracts/contracts/crypto/Verifier.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { Pairing } from "./Pairing.sol";
 import { SnarkConstants } from "./SnarkConstants.sol";
diff --git a/contracts/contracts/gatekeepers/EASGatekeeper.sol b/contracts/contracts/gatekeepers/EASGatekeeper.sol
index 0379a8cab8..ad080f4a47 100644
--- a/contracts/contracts/gatekeepers/EASGatekeeper.sol
+++ b/contracts/contracts/gatekeepers/EASGatekeeper.sol
@@ -9,7 +9,7 @@ import { IEAS } from "../interfaces/IEAS.sol";
 /// @title EASGatekeeper
 /// @notice A gatekeeper contract which allows users to sign up to MACI
 /// only if they've received an attestation of a specific schema from a trusted attester
-contract EASGatekeeper is SignUpGatekeeper, Ownable {
+contract EASGatekeeper is SignUpGatekeeper, Ownable(msg.sender) {
   // the reference to the EAS contract
   IEAS private immutable eas;
 
@@ -38,7 +38,7 @@ contract EASGatekeeper is SignUpGatekeeper, Ownable {
   /// @param _eas The EAS contract
   /// @param _attester The trusted attester
   /// @param _schema The schema UID
-  constructor(address _eas, address _attester, bytes32 _schema) payable Ownable() {
+  constructor(address _eas, address _attester, bytes32 _schema) payable {
     if (_eas == address(0) || _attester == address(0)) revert ZeroAddress();
     eas = IEAS(_eas);
     schema = _schema;
diff --git a/contracts/contracts/gatekeepers/FreeForAllSignUpGatekeeper.sol b/contracts/contracts/gatekeepers/FreeForAllSignUpGatekeeper.sol
index 9637e02d63..09a4b0d1a7 100644
--- a/contracts/contracts/gatekeepers/FreeForAllSignUpGatekeeper.sol
+++ b/contracts/contracts/gatekeepers/FreeForAllSignUpGatekeeper.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { SignUpGatekeeper } from "./SignUpGatekeeper.sol";
 
diff --git a/contracts/contracts/gatekeepers/HatsGatekeeperBase.sol b/contracts/contracts/gatekeepers/HatsGatekeeperBase.sol
index 6eda9e9e05..566c2b47f0 100644
--- a/contracts/contracts/gatekeepers/HatsGatekeeperBase.sol
+++ b/contracts/contracts/gatekeepers/HatsGatekeeperBase.sol
@@ -8,7 +8,7 @@ import { SignUpGatekeeper } from "./SignUpGatekeeper.sol";
 
 /// @title HatsGatekeeperBase
 /// @notice Abstract contract containing the base elements of a Hats Gatekeeper contract
-abstract contract HatsGatekeeperBase is SignUpGatekeeper, Ownable {
+abstract contract HatsGatekeeperBase is SignUpGatekeeper, Ownable(msg.sender) {
   /*//////////////////////////////////////////////////////////////
                               CUSTOM ERRORS
     //////////////////////////////////////////////////////////////*/
diff --git a/contracts/contracts/gatekeepers/SignUpGatekeeper.sol b/contracts/contracts/gatekeepers/SignUpGatekeeper.sol
index 2e1a23b1ff..4cebc106d8 100644
--- a/contracts/contracts/gatekeepers/SignUpGatekeeper.sol
+++ b/contracts/contracts/gatekeepers/SignUpGatekeeper.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 /// @title SignUpGatekeeper
 /// @notice A gatekeeper contract which allows users to sign up for a poll.
diff --git a/contracts/contracts/gatekeepers/SignUpTokenGatekeeper.sol b/contracts/contracts/gatekeepers/SignUpTokenGatekeeper.sol
index e3dcfd7308..bc62b523ea 100644
--- a/contracts/contracts/gatekeepers/SignUpTokenGatekeeper.sol
+++ b/contracts/contracts/gatekeepers/SignUpTokenGatekeeper.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
 
@@ -9,7 +9,7 @@ import { SignUpToken } from "../SignUpToken.sol";
 /// @title SignUpTokenGatekeeper
 /// @notice This contract allows to gatekeep MACI signups
 /// by requiring new voters to own a certain ERC721 token
-contract SignUpTokenGatekeeper is SignUpGatekeeper, Ownable {
+contract SignUpTokenGatekeeper is SignUpGatekeeper, Ownable(msg.sender) {
   /// @notice the reference to the SignUpToken contract
   SignUpToken public token;
   /// @notice the reference to the MACI contract
@@ -25,7 +25,7 @@ contract SignUpTokenGatekeeper is SignUpGatekeeper, Ownable {
 
   /// @notice creates a new SignUpTokenGatekeeper
   /// @param _token the address of the SignUpToken contract
-  constructor(SignUpToken _token) payable Ownable() {
+  constructor(SignUpToken _token) payable {
     token = _token;
   }
 
diff --git a/contracts/contracts/initialVoiceCreditProxy/ConstantInitialVoiceCreditProxy.sol b/contracts/contracts/initialVoiceCreditProxy/ConstantInitialVoiceCreditProxy.sol
index d9aefa7a0d..b5d6db4f3d 100644
--- a/contracts/contracts/initialVoiceCreditProxy/ConstantInitialVoiceCreditProxy.sol
+++ b/contracts/contracts/initialVoiceCreditProxy/ConstantInitialVoiceCreditProxy.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { InitialVoiceCreditProxy } from "./InitialVoiceCreditProxy.sol";
 
diff --git a/contracts/contracts/initialVoiceCreditProxy/InitialVoiceCreditProxy.sol b/contracts/contracts/initialVoiceCreditProxy/InitialVoiceCreditProxy.sol
index 246ec33729..6531fdf7d3 100644
--- a/contracts/contracts/initialVoiceCreditProxy/InitialVoiceCreditProxy.sol
+++ b/contracts/contracts/initialVoiceCreditProxy/InitialVoiceCreditProxy.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 /// @title InitialVoiceCreditProxy
 /// @notice This contract is the base contract for
diff --git a/contracts/contracts/interfaces/IMACI.sol b/contracts/contracts/interfaces/IMACI.sol
index 3060bc9ab5..2323c4fcde 100644
--- a/contracts/contracts/interfaces/IMACI.sol
+++ b/contracts/contracts/interfaces/IMACI.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { AccQueue } from "../trees/AccQueue.sol";
 
diff --git a/contracts/contracts/trees/AccQueue.sol b/contracts/contracts/trees/AccQueue.sol
index 7e1f6fe2a9..ef6de8af03 100644
--- a/contracts/contracts/trees/AccQueue.sol
+++ b/contracts/contracts/trees/AccQueue.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
 import { Hasher } from "../crypto/Hasher.sol";
@@ -10,7 +10,7 @@ import { Hasher } from "../crypto/Hasher.sol";
 /// subtrees together. Merging subtrees requires at least 2 operations:
 /// mergeSubRoots(), and merge(). To get around the gas limit,
 /// the mergeSubRoots() can be performed in multiple transactions.
-abstract contract AccQueue is Ownable, Hasher {
+abstract contract AccQueue is Ownable(msg.sender), Hasher {
   // The maximum tree depth
   uint256 public constant MAX_DEPTH = 32;
 
diff --git a/contracts/contracts/trees/AccQueueBinary.sol b/contracts/contracts/trees/AccQueueBinary.sol
index c66172d189..c652b18bd7 100644
--- a/contracts/contracts/trees/AccQueueBinary.sol
+++ b/contracts/contracts/trees/AccQueueBinary.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { AccQueue } from "./AccQueue.sol";
 
diff --git a/contracts/contracts/trees/AccQueueBinary0.sol b/contracts/contracts/trees/AccQueueBinary0.sol
index 93fe50ce56..33c5eeba14 100644
--- a/contracts/contracts/trees/AccQueueBinary0.sol
+++ b/contracts/contracts/trees/AccQueueBinary0.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { MerkleZeros as MerkleBinary0 } from "./zeros/MerkleBinary0.sol";
 import { AccQueueBinary } from "./AccQueueBinary.sol";
diff --git a/contracts/contracts/trees/AccQueueBinaryMaci.sol b/contracts/contracts/trees/AccQueueBinaryMaci.sol
index 5d545f2b00..0291e9d322 100644
--- a/contracts/contracts/trees/AccQueueBinaryMaci.sol
+++ b/contracts/contracts/trees/AccQueueBinaryMaci.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { MerkleZeros as MerkleBinaryMaci } from "./zeros/MerkleBinaryMaci.sol";
 import { AccQueueBinary } from "./AccQueueBinary.sol";
diff --git a/contracts/contracts/trees/AccQueueQuinary.sol b/contracts/contracts/trees/AccQueueQuinary.sol
index 25d8d3d3e4..c31d54dd2c 100644
--- a/contracts/contracts/trees/AccQueueQuinary.sol
+++ b/contracts/contracts/trees/AccQueueQuinary.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { AccQueue } from "./AccQueue.sol";
 
diff --git a/contracts/contracts/trees/AccQueueQuinary0.sol b/contracts/contracts/trees/AccQueueQuinary0.sol
index f8edfcfc04..9ac606a5c8 100644
--- a/contracts/contracts/trees/AccQueueQuinary0.sol
+++ b/contracts/contracts/trees/AccQueueQuinary0.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { MerkleZeros as MerkleQuinary0 } from "./zeros/MerkleQuinary0.sol";
 import { AccQueueQuinary } from "./AccQueueQuinary.sol";
diff --git a/contracts/contracts/trees/AccQueueQuinaryBlankSl.sol b/contracts/contracts/trees/AccQueueQuinaryBlankSl.sol
index ca7e8c1741..c629677cd8 100644
--- a/contracts/contracts/trees/AccQueueQuinaryBlankSl.sol
+++ b/contracts/contracts/trees/AccQueueQuinaryBlankSl.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { MerkleZeros as MerkleQuinaryBlankSl } from "./zeros/MerkleQuinaryBlankSl.sol";
 import { AccQueueQuinary } from "./AccQueueQuinary.sol";
diff --git a/contracts/contracts/trees/AccQueueQuinaryMaci.sol b/contracts/contracts/trees/AccQueueQuinaryMaci.sol
index 01980fc37a..cfb5533311 100644
--- a/contracts/contracts/trees/AccQueueQuinaryMaci.sol
+++ b/contracts/contracts/trees/AccQueueQuinaryMaci.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { MerkleZeros as MerkleQuinaryMaci } from "./zeros/MerkleQuinaryMaci.sol";
 import { AccQueueQuinary } from "./AccQueueQuinary.sol";
diff --git a/contracts/contracts/trees/EmptyBallotRoots.sol b/contracts/contracts/trees/EmptyBallotRoots.sol
index 854685c95d..4dc8cd6862 100644
--- a/contracts/contracts/trees/EmptyBallotRoots.sol
+++ b/contracts/contracts/trees/EmptyBallotRoots.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 abstract contract EmptyBallotRoots {
   // emptyBallotRoots contains the roots of Ballot trees of five leaf
diff --git a/contracts/contracts/trees/zeros/MerkleBinary0.sol b/contracts/contracts/trees/zeros/MerkleBinary0.sol
index 91e0ac1c48..3ff547ff70 100644
--- a/contracts/contracts/trees/zeros/MerkleBinary0.sol
+++ b/contracts/contracts/trees/zeros/MerkleBinary0.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 abstract contract MerkleZeros {
   uint256[33] internal zeros;
diff --git a/contracts/contracts/trees/zeros/MerkleBinaryMaci.sol b/contracts/contracts/trees/zeros/MerkleBinaryMaci.sol
index 2fd0a3ba0e..370efb087c 100644
--- a/contracts/contracts/trees/zeros/MerkleBinaryMaci.sol
+++ b/contracts/contracts/trees/zeros/MerkleBinaryMaci.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 abstract contract MerkleZeros {
   uint256[33] internal zeros;
diff --git a/contracts/contracts/trees/zeros/MerkleQuinary0.sol b/contracts/contracts/trees/zeros/MerkleQuinary0.sol
index 31d363f48e..e8806376bb 100644
--- a/contracts/contracts/trees/zeros/MerkleQuinary0.sol
+++ b/contracts/contracts/trees/zeros/MerkleQuinary0.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 abstract contract MerkleZeros {
   uint256[33] internal zeros;
diff --git a/contracts/contracts/trees/zeros/MerkleQuinaryBlankSl.sol b/contracts/contracts/trees/zeros/MerkleQuinaryBlankSl.sol
index 2f673546fd..4f3a8fe09d 100644
--- a/contracts/contracts/trees/zeros/MerkleQuinaryBlankSl.sol
+++ b/contracts/contracts/trees/zeros/MerkleQuinaryBlankSl.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 abstract contract MerkleZeros {
   uint256[33] internal zeros;
diff --git a/contracts/contracts/trees/zeros/MerkleQuinaryMaci.sol b/contracts/contracts/trees/zeros/MerkleQuinaryMaci.sol
index 769b138b00..c120dbec49 100644
--- a/contracts/contracts/trees/zeros/MerkleQuinaryMaci.sol
+++ b/contracts/contracts/trees/zeros/MerkleQuinaryMaci.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 abstract contract MerkleZeros {
   uint256[33] internal zeros;
diff --git a/contracts/contracts/trees/zeros/MerkleQuinaryMaciWithSha256.sol b/contracts/contracts/trees/zeros/MerkleQuinaryMaciWithSha256.sol
index d5f4001482..f21468cf9d 100644
--- a/contracts/contracts/trees/zeros/MerkleQuinaryMaciWithSha256.sol
+++ b/contracts/contracts/trees/zeros/MerkleQuinaryMaciWithSha256.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 abstract contract MerkleZeros {
   uint256[33] internal zeros;
diff --git a/contracts/contracts/utilities/CommonUtilities.sol b/contracts/contracts/utilities/CommonUtilities.sol
index 901d017ad4..01d99ff0fe 100644
--- a/contracts/contracts/utilities/CommonUtilities.sol
+++ b/contracts/contracts/utilities/CommonUtilities.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { IPoll } from "../interfaces/IPoll.sol";
 
diff --git a/contracts/contracts/utilities/DomainObjs.sol b/contracts/contracts/utilities/DomainObjs.sol
index 41b0f7b12d..c5bbb1072d 100644
--- a/contracts/contracts/utilities/DomainObjs.sol
+++ b/contracts/contracts/utilities/DomainObjs.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 /// @title DomainObjs
 /// @notice An utility contract that holds
diff --git a/contracts/contracts/utilities/Params.sol b/contracts/contracts/utilities/Params.sol
index 8d48e19213..a3ad64d5cc 100644
--- a/contracts/contracts/utilities/Params.sol
+++ b/contracts/contracts/utilities/Params.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 import { IMACI } from "../interfaces/IMACI.sol";
 import { AccQueue } from "../trees/AccQueue.sol";
diff --git a/contracts/contracts/utilities/Utilities.sol b/contracts/contracts/utilities/Utilities.sol
index 488bf39896..6a5216c7f6 100644
--- a/contracts/contracts/utilities/Utilities.sol
+++ b/contracts/contracts/utilities/Utilities.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 import { DomainObjs } from "./DomainObjs.sol";
 import { Hasher } from "../crypto/Hasher.sol";
 import { SnarkConstants } from "../crypto/SnarkConstants.sol";
diff --git a/contracts/hardhat.config.ts b/contracts/hardhat.config.ts
index a88f232555..a6ea992a10 100644
--- a/contracts/hardhat.config.ts
+++ b/contracts/hardhat.config.ts
@@ -47,7 +47,7 @@ const getCommonNetworkConfig = (networkName: ESupportedChains, chainId: number,
 
 const config: HardhatUserConfig = {
   solidity: {
-    version: "0.8.10",
+    version: "0.8.20",
     settings: {
       optimizer: {
         enabled: true,
diff --git a/contracts/package.json b/contracts/package.json
index 6963bfc1ab..7388bf6d92 100644
--- a/contracts/package.json
+++ b/contracts/package.json
@@ -72,7 +72,7 @@
   "dependencies": {
     "@nomicfoundation/hardhat-ethers": "^3.0.5",
     "@nomicfoundation/hardhat-toolbox": "^5.0.0",
-    "@openzeppelin/contracts": "^4.8.0",
+    "@openzeppelin/contracts": "^5.0.2",
     "circomlibjs": "^0.1.7",
     "ethers": "^6.11.1",
     "hardhat": "^2.22.2",
diff --git a/contracts/templates/EmptyBallotRoots.sol.template b/contracts/templates/EmptyBallotRoots.sol.template
index f0ce1bf8b9..66f440d909 100644
--- a/contracts/templates/EmptyBallotRoots.sol.template
+++ b/contracts/templates/EmptyBallotRoots.sol.template
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 abstract contract EmptyBallotRoots {
   // emptyBallotRoots contains the roots of Ballot trees of five leaf
diff --git a/contracts/templates/MerkleZeros.sol.template b/contracts/templates/MerkleZeros.sol.template
index 6e7d0114f0..0cc463c8f0 100644
--- a/contracts/templates/MerkleZeros.sol.template
+++ b/contracts/templates/MerkleZeros.sol.template
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.10;
+pragma solidity ^0.8.20;
 
 abstract contract MerkleZeros {
   uint256[<% NUM_ZEROS %>] internal zeros;
diff --git a/contracts/tests/EASGatekeeper.test.ts b/contracts/tests/EASGatekeeper.test.ts
index a8448f52ab..74e453fa26 100644
--- a/contracts/tests/EASGatekeeper.test.ts
+++ b/contracts/tests/EASGatekeeper.test.ts
@@ -101,8 +101,9 @@ describe("EAS Gatekeeper", () => {
 
     it("should fail to set MACI instance when the caller is not the owner", async () => {
       const [, secondSigner] = await getSigners();
-      await expect(easGatekeeper.connect(secondSigner).setMaciInstance(signerAddress)).to.be.revertedWith(
-        "Ownable: caller is not the owner",
+      await expect(easGatekeeper.connect(secondSigner).setMaciInstance(signerAddress)).to.be.revertedWithCustomError(
+        easGatekeeper,
+        "OwnableUnauthorizedAccount",
       );
     });
 
diff --git a/contracts/tests/HatsGatekeeper.test.ts b/contracts/tests/HatsGatekeeper.test.ts
index 049f188981..0c55ac260a 100644
--- a/contracts/tests/HatsGatekeeper.test.ts
+++ b/contracts/tests/HatsGatekeeper.test.ts
@@ -150,8 +150,9 @@ describe("HatsProtocol Gatekeeper", () => {
       });
 
       it("should fail to set MACI instance when the caller is not the owner", async () => {
-        await expect(hatsGatekeeperSingle.connect(voter).setMaciInstance(signerAddress)).to.be.revertedWith(
-          "Ownable: caller is not the owner",
+        await expect(hatsGatekeeperSingle.connect(voter).setMaciInstance(signerAddress)).to.be.revertedWithCustomError(
+          hatsGatekeeperSingle,
+          "OwnableUnauthorizedAccount",
         );
       });
     });
@@ -252,9 +253,9 @@ describe("HatsProtocol Gatekeeper", () => {
       });
 
       it("should fail to set MACI instance when the caller is not the owner", async () => {
-        await expect(hatsGatekeeperMultiple.connect(voter).setMaciInstance(signerAddress)).to.be.revertedWith(
-          "Ownable: caller is not the owner",
-        );
+        await expect(
+          hatsGatekeeperMultiple.connect(voter).setMaciInstance(signerAddress),
+        ).to.be.revertedWithCustomError(hatsGatekeeperMultiple, "OwnableUnauthorizedAccount");
       });
     });
 
diff --git a/contracts/tests/Poll.test.ts b/contracts/tests/Poll.test.ts
index 97e9ac334e..1a7c36630e 100644
--- a/contracts/tests/Poll.test.ts
+++ b/contracts/tests/Poll.test.ts
@@ -11,9 +11,10 @@ import { getDefaultSigner, getSigners } from "../ts/utils";
 import {
   AccQueue,
   AccQueueQuinaryMaci__factory as AccQueueQuinaryMaciFactory,
+  Poll__factory as PollFactory,
+  IERC20Errors__factory as IERC20ErrorsFactory,
   MACI,
   Poll as PollContract,
-  Poll__factory as PollFactory,
   TopupCredit,
   Verifier,
   VkRegistry,
@@ -162,7 +163,12 @@ describe("Poll", () => {
     });
 
     it("should throw when the user does not have enough tokens", async () => {
-      await expect(pollContract.connect(signer).topup(1n, 50n)).to.be.revertedWith("ERC20: insufficient allowance");
+      const pollAddress = await pollContract.getAddress();
+
+      await expect(pollContract.connect(signer).topup(1n, 50n)).to.be.revertedWithCustomError(
+        IERC20ErrorsFactory.connect(pollAddress),
+        "ERC20InsufficientAllowance",
+      );
     });
 
     it("should emit an event when publishing a topup message", async () => {
diff --git a/integrationTests/hardhat.config.ts b/integrationTests/hardhat.config.ts
index f9fca4b4c0..3562d475d2 100644
--- a/integrationTests/hardhat.config.ts
+++ b/integrationTests/hardhat.config.ts
@@ -19,7 +19,7 @@ const config: HardhatUserConfig = {
     },
   },
   solidity: {
-    version: "0.8.10",
+    version: "0.8.20",
     settings: {
       optimizer: {
         enabled: true,
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 1c96e0660c..3dc8814dea 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -230,8 +230,8 @@ importers:
         specifier: ^5.0.0
         version: 5.0.0(@nomicfoundation/hardhat-chai-matchers@2.0.6)(@nomicfoundation/hardhat-ethers@3.0.5)(@nomicfoundation/hardhat-ignition-ethers@0.15.1)(@nomicfoundation/hardhat-network-helpers@1.0.10)(@nomicfoundation/hardhat-verify@2.0.5)(@typechain/ethers-v6@0.5.1)(@typechain/hardhat@9.1.0)(@types/chai@4.3.14)(@types/mocha@10.0.6)(@types/node@20.12.7)(chai@4.4.1)(ethers@6.11.1)(hardhat-gas-reporter@1.0.10)(hardhat@2.22.2)(solidity-coverage@0.8.12)(ts-node@10.9.2)(typechain@8.3.2)(typescript@5.4.5)
       '@openzeppelin/contracts':
-        specifier: ^4.8.0
-        version: 4.9.6
+        specifier: ^5.0.2
+        version: 5.0.2
       circomlibjs:
         specifier: ^0.1.7
         version: 0.1.7
@@ -4612,8 +4612,8 @@ packages:
       '@octokit/openapi-types': 18.1.1
     dev: true
 
-  /@openzeppelin/contracts@4.9.6:
-    resolution: {integrity: sha512-xSmezSupL+y9VkHZJGDoCBpmnB2ogM13ccaYDWqJTfS3dbuHkgjuwDFUmaFauBCboQMGB/S5UqUl2y54X99BmA==}
+  /@openzeppelin/contracts@5.0.2:
+    resolution: {integrity: sha512-ytPc6eLGcHHnapAZ9S+5qsdomhjo6QBHTDRRBFfTxXIpsicMhVPouPgmUPebZZZGX7vt9USA+Z+0M0dSVtSUEA==}
     dev: false
 
   /@pkgjs/parseargs@0.11.0: