diff --git a/.solhint.json b/.solhint.json
index 82f1dbede..b131847ba 100644
--- a/.solhint.json
+++ b/.solhint.json
@@ -4,7 +4,7 @@
     "func-order": "off",
     "mark-callable-contracts": "off",
     "no-empty-blocks": "off",
-    "compiler-version": ["error", "^0.6.0"],
+    "compiler-version": ["error", "^0.7.0"],
     "private-vars-leading-underscore": "error"
   }
 }
diff --git a/README.md b/README.md
index 0c993c135..cfadb9c69 100644
--- a/README.md
+++ b/README.md
@@ -28,12 +28,12 @@ OpenZeppelin Contracts features a [stable API](https://docs.openzeppelin.com/con
 Once installed, you can use the contracts in the library by importing them:
 
 ```solidity
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
 
 contract MyCollectible is ERC721 {
-    constructor() ERC721("MyCollectible", "MCO") public {
+    constructor() ERC721("MyCollectible", "MCO") {
     }
 }
 ```
diff --git a/contracts/GSN/Context.sol b/contracts/GSN/Context.sol
index 337acb193..26e56a02d 100644
--- a/contracts/GSN/Context.sol
+++ b/contracts/GSN/Context.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /*
  * @dev Provides information about the current execution context, including the
diff --git a/contracts/GSN/GSNRecipient.sol b/contracts/GSN/GSNRecipient.sol
index a719ab87f..dd941f9e9 100644
--- a/contracts/GSN/GSNRecipient.sol
+++ b/contracts/GSN/GSNRecipient.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./IRelayRecipient.sol";
 import "./IRelayHub.sol";
diff --git a/contracts/GSN/GSNRecipientERC20Fee.sol b/contracts/GSN/GSNRecipientERC20Fee.sol
index 240532556..ad5dee054 100644
--- a/contracts/GSN/GSNRecipientERC20Fee.sol
+++ b/contracts/GSN/GSNRecipientERC20Fee.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./GSNRecipient.sol";
 import "../math/SafeMath.sol";
@@ -30,7 +30,7 @@ contract GSNRecipientERC20Fee is GSNRecipient {
     /**
      * @dev The arguments to the constructor are the details that the gas payment token will have: `name` and `symbol`. `decimals` is hard-coded to 18.
      */
-    constructor(string memory name, string memory symbol) public {
+    constructor(string memory name, string memory symbol) {
         _token = new __unstable__ERC20Owned(name, symbol);
     }
 
@@ -116,7 +116,7 @@ contract GSNRecipientERC20Fee is GSNRecipient {
 contract __unstable__ERC20Owned is ERC20, Ownable {
     uint256 private constant _UINT256_MAX = 2**256 - 1;
 
-    constructor(string memory name, string memory symbol) public ERC20(name, symbol) { }
+    constructor(string memory name, string memory symbol) ERC20(name, symbol) { }
 
     // The owner (GSNRecipientERC20Fee) can mint tokens
     function mint(address account, uint256 amount) public onlyOwner {
diff --git a/contracts/GSN/GSNRecipientSignature.sol b/contracts/GSN/GSNRecipientSignature.sol
index ee514de6e..3955db595 100644
--- a/contracts/GSN/GSNRecipientSignature.sol
+++ b/contracts/GSN/GSNRecipientSignature.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./GSNRecipient.sol";
 import "../cryptography/ECDSA.sol";
@@ -23,7 +23,7 @@ contract GSNRecipientSignature is GSNRecipient {
     /**
      * @dev Sets the trusted signer that is going to be producing signatures to approve relayed calls.
      */
-    constructor(address trustedSigner) public {
+    constructor(address trustedSigner) {
         require(trustedSigner != address(0), "GSNRecipientSignature: trusted signer is the zero address");
         _trustedSigner = trustedSigner;
     }
diff --git a/contracts/GSN/IRelayHub.sol b/contracts/GSN/IRelayHub.sol
index 30b0ab951..774add719 100644
--- a/contracts/GSN/IRelayHub.sol
+++ b/contracts/GSN/IRelayHub.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Interface for `RelayHub`, the core contract of the GSN. Users should not need to interact with this contract
diff --git a/contracts/GSN/IRelayRecipient.sol b/contracts/GSN/IRelayRecipient.sol
index be0ffe56f..843338fd1 100644
--- a/contracts/GSN/IRelayRecipient.sol
+++ b/contracts/GSN/IRelayRecipient.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Base interface for a contract that will be called via the GSN from {IRelayHub}.
diff --git a/contracts/access/AccessControl.sol b/contracts/access/AccessControl.sol
index 27ba9e8dc..42c8d2560 100644
--- a/contracts/access/AccessControl.sol
+++ b/contracts/access/AccessControl.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../utils/EnumerableSet.sol";
 import "../utils/Address.sol";
diff --git a/contracts/access/Ownable.sol b/contracts/access/Ownable.sol
index 353e79c2c..e68731881 100644
--- a/contracts/access/Ownable.sol
+++ b/contracts/access/Ownable.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../GSN/Context.sol";
 /**
@@ -23,7 +23,7 @@ contract Ownable is Context {
     /**
      * @dev Initializes the contract setting the deployer as the initial owner.
      */
-    constructor () internal {
+    constructor () {
         address msgSender = _msgSender();
         _owner = msgSender;
         emit OwnershipTransferred(address(0), msgSender);
diff --git a/contracts/cryptography/ECDSA.sol b/contracts/cryptography/ECDSA.sol
index 5a85ed963..59c328e20 100644
--- a/contracts/cryptography/ECDSA.sol
+++ b/contracts/cryptography/ECDSA.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
diff --git a/contracts/cryptography/MerkleProof.sol b/contracts/cryptography/MerkleProof.sol
index 8a5fc90f5..7207cb584 100644
--- a/contracts/cryptography/MerkleProof.sol
+++ b/contracts/cryptography/MerkleProof.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev These functions deal with verification of Merkle trees (hash trees),
diff --git a/contracts/introspection/ERC165.sol b/contracts/introspection/ERC165.sol
index 8f34a88ac..5a0ca2425 100644
--- a/contracts/introspection/ERC165.sol
+++ b/contracts/introspection/ERC165.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./IERC165.sol";
 
@@ -21,7 +21,7 @@ contract ERC165 is IERC165 {
      */
     mapping(bytes4 => bool) private _supportedInterfaces;
 
-    constructor () internal {
+    constructor () {
         // Derived contracts need only register support for their own interfaces,
         // we register support for ERC165 itself here
         _registerInterface(_INTERFACE_ID_ERC165);
diff --git a/contracts/introspection/ERC165Checker.sol b/contracts/introspection/ERC165Checker.sol
index 5469e020a..03ed537ee 100644
--- a/contracts/introspection/ERC165Checker.sol
+++ b/contracts/introspection/ERC165Checker.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.2;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Library used to query support of an interface declared via {IERC165}.
diff --git a/contracts/introspection/ERC1820Implementer.sol b/contracts/introspection/ERC1820Implementer.sol
index df740a7a5..dd7731c1c 100644
--- a/contracts/introspection/ERC1820Implementer.sol
+++ b/contracts/introspection/ERC1820Implementer.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./IERC1820Implementer.sol";
 
diff --git a/contracts/introspection/IERC165.sol b/contracts/introspection/IERC165.sol
index 425458d69..4d5d76684 100644
--- a/contracts/introspection/IERC165.sol
+++ b/contracts/introspection/IERC165.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Interface of the ERC165 standard, as defined in the
diff --git a/contracts/introspection/IERC1820Implementer.sol b/contracts/introspection/IERC1820Implementer.sol
index 1eb89e78d..024c759d3 100644
--- a/contracts/introspection/IERC1820Implementer.sol
+++ b/contracts/introspection/IERC1820Implementer.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Interface for an ERC1820 implementer, as defined in the
diff --git a/contracts/introspection/IERC1820Registry.sol b/contracts/introspection/IERC1820Registry.sol
index be92e465a..cd9bd5b4e 100644
--- a/contracts/introspection/IERC1820Registry.sol
+++ b/contracts/introspection/IERC1820Registry.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Interface of the global ERC1820 Registry, as defined in the
diff --git a/contracts/math/Math.sol b/contracts/math/Math.sol
index ec4ac227d..a4c5c4eac 100644
--- a/contracts/math/Math.sol
+++ b/contracts/math/Math.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Standard math utilities missing in the Solidity language.
diff --git a/contracts/math/SafeMath.sol b/contracts/math/SafeMath.sol
index 80490effe..4b2a49d47 100644
--- a/contracts/math/SafeMath.sol
+++ b/contracts/math/SafeMath.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Wrappers over Solidity's arithmetic operations with added overflow
diff --git a/contracts/math/SignedSafeMath.sol b/contracts/math/SignedSafeMath.sol
index a8f51dc3d..6eee7d093 100644
--- a/contracts/math/SignedSafeMath.sol
+++ b/contracts/math/SignedSafeMath.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @title SignedSafeMath
diff --git a/contracts/mocks/AccessControlMock.sol b/contracts/mocks/AccessControlMock.sol
index 2f31a7a69..7cd2c8e33 100644
--- a/contracts/mocks/AccessControlMock.sol
+++ b/contracts/mocks/AccessControlMock.sol
@@ -1,11 +1,11 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../access/AccessControl.sol";
 
 contract AccessControlMock is AccessControl {
-    constructor() public {
+    constructor() {
         _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
     }
 
diff --git a/contracts/mocks/AddressImpl.sol b/contracts/mocks/AddressImpl.sol
index 19dcb15b4..fa3d887c0 100644
--- a/contracts/mocks/AddressImpl.sol
+++ b/contracts/mocks/AddressImpl.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../utils/Address.sol";
 
diff --git a/contracts/mocks/ArraysImpl.sol b/contracts/mocks/ArraysImpl.sol
index b4bfcf1fb..0302b2662 100644
--- a/contracts/mocks/ArraysImpl.sol
+++ b/contracts/mocks/ArraysImpl.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../utils/Arrays.sol";
 
@@ -9,7 +9,7 @@ contract ArraysImpl {
 
     uint256[] private _array;
 
-    constructor (uint256[] memory array) public {
+    constructor (uint256[] memory array) {
         _array = array;
     }
 
diff --git a/contracts/mocks/CallReceiverMock.sol b/contracts/mocks/CallReceiverMock.sol
index 2e3297617..139ac1eeb 100644
--- a/contracts/mocks/CallReceiverMock.sol
+++ b/contracts/mocks/CallReceiverMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 contract CallReceiverMock {
 
diff --git a/contracts/mocks/ConditionalEscrowMock.sol b/contracts/mocks/ConditionalEscrowMock.sol
index a93b2d760..518481e95 100644
--- a/contracts/mocks/ConditionalEscrowMock.sol
+++ b/contracts/mocks/ConditionalEscrowMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../payment/escrow/ConditionalEscrow.sol";
 
diff --git a/contracts/mocks/ContextMock.sol b/contracts/mocks/ContextMock.sol
index ec7c8844c..6080971cb 100644
--- a/contracts/mocks/ContextMock.sol
+++ b/contracts/mocks/ContextMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../GSN/Context.sol";
 
diff --git a/contracts/mocks/CountersImpl.sol b/contracts/mocks/CountersImpl.sol
index 46f9ef9e0..4f8a49afb 100644
--- a/contracts/mocks/CountersImpl.sol
+++ b/contracts/mocks/CountersImpl.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../utils/Counters.sol";
 
diff --git a/contracts/mocks/Create2Impl.sol b/contracts/mocks/Create2Impl.sol
index 542f0fc4e..06b76435d 100644
--- a/contracts/mocks/Create2Impl.sol
+++ b/contracts/mocks/Create2Impl.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../utils/Create2.sol";
 import "../introspection/ERC1820Implementer.sol";
diff --git a/contracts/mocks/ECDSAMock.sol b/contracts/mocks/ECDSAMock.sol
index d1e135000..efb0c79f8 100644
--- a/contracts/mocks/ECDSAMock.sol
+++ b/contracts/mocks/ECDSAMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../cryptography/ECDSA.sol";
 
diff --git a/contracts/mocks/ERC1155BurnableMock.sol b/contracts/mocks/ERC1155BurnableMock.sol
index cce25894b..9e77288a6 100644
--- a/contracts/mocks/ERC1155BurnableMock.sol
+++ b/contracts/mocks/ERC1155BurnableMock.sol
@@ -1,11 +1,11 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC1155/ERC1155Burnable.sol";
 
 contract ERC1155BurnableMock is ERC1155Burnable {
-    constructor(string memory uri) public ERC1155(uri) { }
+    constructor(string memory uri) ERC1155(uri) { }
 
     function mint(address to, uint256 id, uint256 value, bytes memory data) public {
         _mint(to, id, value, data);
diff --git a/contracts/mocks/ERC1155Mock.sol b/contracts/mocks/ERC1155Mock.sol
index 5b66cfe8e..f403745f3 100644
--- a/contracts/mocks/ERC1155Mock.sol
+++ b/contracts/mocks/ERC1155Mock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC1155/ERC1155.sol";
 
@@ -9,7 +9,7 @@ import "../token/ERC1155/ERC1155.sol";
  * This mock just publicizes internal functions for testing purposes
  */
 contract ERC1155Mock is ERC1155 {
-    constructor (string memory uri) public ERC1155(uri) {
+    constructor (string memory uri) ERC1155(uri) {
         // solhint-disable-previous-line no-empty-blocks
     }
 
diff --git a/contracts/mocks/ERC1155PausableMock.sol b/contracts/mocks/ERC1155PausableMock.sol
index d76fe8123..5c3bb1764 100644
--- a/contracts/mocks/ERC1155PausableMock.sol
+++ b/contracts/mocks/ERC1155PausableMock.sol
@@ -1,12 +1,12 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./ERC1155Mock.sol";
 import "../token/ERC1155/ERC1155Pausable.sol";
 
 contract ERC1155PausableMock is ERC1155Mock, ERC1155Pausable {
-    constructor(string memory uri) public ERC1155Mock(uri) { }
+    constructor(string memory uri) ERC1155Mock(uri) { }
 
     function pause() external {
         _pause();
diff --git a/contracts/mocks/ERC1155ReceiverMock.sol b/contracts/mocks/ERC1155ReceiverMock.sol
index 145c16352..f5925f8e1 100644
--- a/contracts/mocks/ERC1155ReceiverMock.sol
+++ b/contracts/mocks/ERC1155ReceiverMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC1155/IERC1155Receiver.sol";
 import "./ERC165Mock.sol";
@@ -20,7 +20,6 @@ contract ERC1155ReceiverMock is IERC1155Receiver, ERC165Mock {
         bytes4 batRetval,
         bool batReverts
     )
-        public
     {
         _recRetval = recRetval;
         _recReverts = recReverts;
diff --git a/contracts/mocks/ERC165/ERC165InterfacesSupported.sol b/contracts/mocks/ERC165/ERC165InterfacesSupported.sol
index 32a430c2e..55002cc06 100644
--- a/contracts/mocks/ERC165/ERC165InterfacesSupported.sol
+++ b/contracts/mocks/ERC165/ERC165InterfacesSupported.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../../introspection/IERC165.sol";
 
@@ -29,7 +29,7 @@ contract SupportsInterfaceWithLookupMock is IERC165 {
      * @dev A contract implementing SupportsInterfaceWithLookup
      * implement ERC165 itself.
      */
-    constructor () public {
+    constructor () {
         _registerInterface(INTERFACE_ID_ERC165);
     }
 
@@ -50,7 +50,7 @@ contract SupportsInterfaceWithLookupMock is IERC165 {
 }
 
 contract ERC165InterfacesSupported is SupportsInterfaceWithLookupMock {
-    constructor (bytes4[] memory interfaceIds) public {
+    constructor (bytes4[] memory interfaceIds) {
         for (uint256 i = 0; i < interfaceIds.length; i++) {
             _registerInterface(interfaceIds[i]);
         }
diff --git a/contracts/mocks/ERC165/ERC165NotSupported.sol b/contracts/mocks/ERC165/ERC165NotSupported.sol
index 0a8a2f8cc..cbc584d16 100644
--- a/contracts/mocks/ERC165/ERC165NotSupported.sol
+++ b/contracts/mocks/ERC165/ERC165NotSupported.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 contract ERC165NotSupported { }
diff --git a/contracts/mocks/ERC165CheckerMock.sol b/contracts/mocks/ERC165CheckerMock.sol
index 85093113f..4d6c5fd32 100644
--- a/contracts/mocks/ERC165CheckerMock.sol
+++ b/contracts/mocks/ERC165CheckerMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../introspection/ERC165Checker.sol";
 
diff --git a/contracts/mocks/ERC165Mock.sol b/contracts/mocks/ERC165Mock.sol
index 147039293..1ceb5f325 100644
--- a/contracts/mocks/ERC165Mock.sol
+++ b/contracts/mocks/ERC165Mock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../introspection/ERC165.sol";
 
diff --git a/contracts/mocks/ERC1820ImplementerMock.sol b/contracts/mocks/ERC1820ImplementerMock.sol
index 18b75672b..8908d62f1 100644
--- a/contracts/mocks/ERC1820ImplementerMock.sol
+++ b/contracts/mocks/ERC1820ImplementerMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../introspection/ERC1820Implementer.sol";
 
diff --git a/contracts/mocks/ERC20BurnableMock.sol b/contracts/mocks/ERC20BurnableMock.sol
index ae777a225..7e61c1543 100644
--- a/contracts/mocks/ERC20BurnableMock.sol
+++ b/contracts/mocks/ERC20BurnableMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC20/ERC20Burnable.sol";
 
@@ -10,7 +10,7 @@ contract ERC20BurnableMock is ERC20Burnable {
         string memory symbol,
         address initialAccount,
         uint256 initialBalance
-    ) public ERC20(name, symbol) {
+    ) ERC20(name, symbol) {
         _mint(initialAccount, initialBalance);
     }
 }
diff --git a/contracts/mocks/ERC20CappedMock.sol b/contracts/mocks/ERC20CappedMock.sol
index 1de31c918..23760f675 100644
--- a/contracts/mocks/ERC20CappedMock.sol
+++ b/contracts/mocks/ERC20CappedMock.sol
@@ -1,12 +1,12 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC20/ERC20Capped.sol";
 
 contract ERC20CappedMock is ERC20Capped {
     constructor (string memory name, string memory symbol, uint256 cap)
-        public ERC20(name, symbol) ERC20Capped(cap)
+        ERC20(name, symbol) ERC20Capped(cap)
     { }
 
     function mint(address to, uint256 tokenId) public {
diff --git a/contracts/mocks/ERC20DecimalsMock.sol b/contracts/mocks/ERC20DecimalsMock.sol
index 8eaf70090..5dc69a4f0 100644
--- a/contracts/mocks/ERC20DecimalsMock.sol
+++ b/contracts/mocks/ERC20DecimalsMock.sol
@@ -1,11 +1,11 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC20/ERC20.sol";
 
 contract ERC20DecimalsMock is ERC20 {
-    constructor (string memory name, string memory symbol, uint8 decimals) public ERC20(name, symbol) {
+    constructor (string memory name, string memory symbol, uint8 decimals) ERC20(name, symbol) {
         _setupDecimals(decimals);
     }
 }
diff --git a/contracts/mocks/ERC20Mock.sol b/contracts/mocks/ERC20Mock.sol
index 525ba6abe..743f6e690 100644
--- a/contracts/mocks/ERC20Mock.sol
+++ b/contracts/mocks/ERC20Mock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC20/ERC20.sol";
 
@@ -11,7 +11,7 @@ contract ERC20Mock is ERC20 {
         string memory symbol,
         address initialAccount,
         uint256 initialBalance
-    ) public payable ERC20(name, symbol) {
+    ) payable ERC20(name, symbol) {
         _mint(initialAccount, initialBalance);
     }
 
diff --git a/contracts/mocks/ERC20PausableMock.sol b/contracts/mocks/ERC20PausableMock.sol
index a6f5cc48d..2b39f2882 100644
--- a/contracts/mocks/ERC20PausableMock.sol
+++ b/contracts/mocks/ERC20PausableMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC20/ERC20Pausable.sol";
 
@@ -11,7 +11,7 @@ contract ERC20PausableMock is ERC20Pausable {
         string memory symbol,
         address initialAccount,
         uint256 initialBalance
-    ) public ERC20(name, symbol) {
+    ) ERC20(name, symbol) {
         _mint(initialAccount, initialBalance);
     }
 
diff --git a/contracts/mocks/ERC20SnapshotMock.sol b/contracts/mocks/ERC20SnapshotMock.sol
index 1fee817c8..412c18fbd 100644
--- a/contracts/mocks/ERC20SnapshotMock.sol
+++ b/contracts/mocks/ERC20SnapshotMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC20/ERC20Snapshot.sol";
 
@@ -11,7 +11,7 @@ contract ERC20SnapshotMock is ERC20Snapshot {
         string memory symbol,
         address initialAccount,
         uint256 initialBalance
-    ) public ERC20(name, symbol) {
+    ) ERC20(name, symbol) {
         _mint(initialAccount, initialBalance);
     }
 
diff --git a/contracts/mocks/ERC721BurnableMock.sol b/contracts/mocks/ERC721BurnableMock.sol
index ee1ca3ff5..2b9735ef4 100644
--- a/contracts/mocks/ERC721BurnableMock.sol
+++ b/contracts/mocks/ERC721BurnableMock.sol
@@ -1,11 +1,11 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC721/ERC721Burnable.sol";
 
 contract ERC721BurnableMock is ERC721Burnable {
-    constructor(string memory name, string memory symbol) public ERC721(name, symbol) { }
+    constructor(string memory name, string memory symbol) ERC721(name, symbol) { }
 
     function mint(address to, uint256 tokenId) public {
         _mint(to, tokenId);
diff --git a/contracts/mocks/ERC721GSNRecipientMock.sol b/contracts/mocks/ERC721GSNRecipientMock.sol
index e761b3f7c..c22defb00 100644
--- a/contracts/mocks/ERC721GSNRecipientMock.sol
+++ b/contracts/mocks/ERC721GSNRecipientMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC721/ERC721.sol";
 import "../GSN/GSNRecipient.sol";
@@ -12,7 +12,6 @@ import "../GSN/GSNRecipientSignature.sol";
  */
 contract ERC721GSNRecipientMock is ERC721, GSNRecipient, GSNRecipientSignature {
     constructor(string memory name, string memory symbol, address trustedSigner)
-        public
         ERC721(name, symbol)
         GSNRecipientSignature(trustedSigner)
     { }
diff --git a/contracts/mocks/ERC721Mock.sol b/contracts/mocks/ERC721Mock.sol
index f2d8ee88e..80d7eec99 100644
--- a/contracts/mocks/ERC721Mock.sol
+++ b/contracts/mocks/ERC721Mock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC721/ERC721.sol";
 
@@ -9,7 +9,7 @@ import "../token/ERC721/ERC721.sol";
  * This mock just provides a public safeMint, mint, and burn functions for testing purposes
  */
 contract ERC721Mock is ERC721 {
-    constructor (string memory name, string memory symbol) public ERC721(name, symbol) { }
+    constructor (string memory name, string memory symbol) ERC721(name, symbol) { }
 
     function exists(uint256 tokenId) public view returns (bool) {
         return _exists(tokenId);
diff --git a/contracts/mocks/ERC721PausableMock.sol b/contracts/mocks/ERC721PausableMock.sol
index edfdc081d..0a16e5b66 100644
--- a/contracts/mocks/ERC721PausableMock.sol
+++ b/contracts/mocks/ERC721PausableMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC721/ERC721Pausable.sol";
 
@@ -9,7 +9,7 @@ import "../token/ERC721/ERC721Pausable.sol";
  * This mock just provides a public mint, burn and exists functions for testing purposes
  */
 contract ERC721PausableMock is ERC721Pausable {
-    constructor (string memory name, string memory symbol) public ERC721(name, symbol) { }
+    constructor (string memory name, string memory symbol) ERC721(name, symbol) { }
 
     function mint(address to, uint256 tokenId) public {
         super._mint(to, tokenId);
diff --git a/contracts/mocks/ERC721ReceiverMock.sol b/contracts/mocks/ERC721ReceiverMock.sol
index 35c794ecd..0d8a370f9 100644
--- a/contracts/mocks/ERC721ReceiverMock.sol
+++ b/contracts/mocks/ERC721ReceiverMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../token/ERC721/IERC721Receiver.sol";
 
@@ -10,7 +10,7 @@ contract ERC721ReceiverMock is IERC721Receiver {
 
     event Received(address operator, address from, uint256 tokenId, bytes data, uint256 gas);
 
-    constructor (bytes4 retval, bool reverts) public {
+    constructor (bytes4 retval, bool reverts) {
         _retval = retval;
         _reverts = reverts;
     }
diff --git a/contracts/mocks/ERC777Mock.sol b/contracts/mocks/ERC777Mock.sol
index 42a02a3d7..b9626d8bb 100644
--- a/contracts/mocks/ERC777Mock.sol
+++ b/contracts/mocks/ERC777Mock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../GSN/Context.sol";
 import "../token/ERC777/ERC777.sol";
@@ -12,7 +12,7 @@ contract ERC777Mock is Context, ERC777 {
         string memory name,
         string memory symbol,
         address[] memory defaultOperators
-    ) public ERC777(name, symbol, defaultOperators) {
+    ) ERC777(name, symbol, defaultOperators) {
         _mint(initialHolder, initialBalance, "", "");
     }
 
diff --git a/contracts/mocks/ERC777SenderRecipientMock.sol b/contracts/mocks/ERC777SenderRecipientMock.sol
index 707eb0182..5c30db58c 100644
--- a/contracts/mocks/ERC777SenderRecipientMock.sol
+++ b/contracts/mocks/ERC777SenderRecipientMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../GSN/Context.sol";
 import "../token/ERC777/IERC777.sol";
diff --git a/contracts/mocks/EnumerableMapMock.sol b/contracts/mocks/EnumerableMapMock.sol
index 8e15be43b..769597d3f 100644
--- a/contracts/mocks/EnumerableMapMock.sol
+++ b/contracts/mocks/EnumerableMapMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../utils/EnumerableMap.sol";
 
diff --git a/contracts/mocks/EnumerableSetMock.sol b/contracts/mocks/EnumerableSetMock.sol
index f9a2c9727..7c47d0543 100644
--- a/contracts/mocks/EnumerableSetMock.sol
+++ b/contracts/mocks/EnumerableSetMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../utils/EnumerableSet.sol";
 
diff --git a/contracts/mocks/EtherReceiverMock.sol b/contracts/mocks/EtherReceiverMock.sol
index 35d502079..aa1ecf9cd 100644
--- a/contracts/mocks/EtherReceiverMock.sol
+++ b/contracts/mocks/EtherReceiverMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 contract EtherReceiverMock {
     bool private _acceptEther;
diff --git a/contracts/mocks/GSNRecipientERC20FeeMock.sol b/contracts/mocks/GSNRecipientERC20FeeMock.sol
index b7f8d6a7d..9ec8c33bb 100644
--- a/contracts/mocks/GSNRecipientERC20FeeMock.sol
+++ b/contracts/mocks/GSNRecipientERC20FeeMock.sol
@@ -1,12 +1,12 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../GSN/GSNRecipient.sol";
 import "../GSN/GSNRecipientERC20Fee.sol";
 
 contract GSNRecipientERC20FeeMock is GSNRecipient, GSNRecipientERC20Fee {
-    constructor(string memory name, string memory symbol) public GSNRecipientERC20Fee(name, symbol) { }
+    constructor(string memory name, string memory symbol) GSNRecipientERC20Fee(name, symbol) { }
 
     function mint(address account, uint256 amount) public {
         _mint(account, amount);
diff --git a/contracts/mocks/GSNRecipientMock.sol b/contracts/mocks/GSNRecipientMock.sol
index d2ba511f3..fc07b61c7 100644
--- a/contracts/mocks/GSNRecipientMock.sol
+++ b/contracts/mocks/GSNRecipientMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./ContextMock.sol";
 import "../GSN/GSNRecipient.sol";
diff --git a/contracts/mocks/GSNRecipientSignatureMock.sol b/contracts/mocks/GSNRecipientSignatureMock.sol
index 7f776e65c..176062204 100644
--- a/contracts/mocks/GSNRecipientSignatureMock.sol
+++ b/contracts/mocks/GSNRecipientSignatureMock.sol
@@ -1,12 +1,12 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../GSN/GSNRecipient.sol";
 import "../GSN/GSNRecipientSignature.sol";
 
 contract GSNRecipientSignatureMock is GSNRecipient, GSNRecipientSignature {
-    constructor(address trustedSigner) public GSNRecipientSignature(trustedSigner) { }
+    constructor(address trustedSigner) GSNRecipientSignature(trustedSigner) { }
 
     event MockFunctionCalled();
 
diff --git a/contracts/mocks/MathMock.sol b/contracts/mocks/MathMock.sol
index 11472f26f..97ec6f1f9 100644
--- a/contracts/mocks/MathMock.sol
+++ b/contracts/mocks/MathMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../math/Math.sol";
 
diff --git a/contracts/mocks/MerkleProofWrapper.sol b/contracts/mocks/MerkleProofWrapper.sol
index 9f6da8a15..398782214 100644
--- a/contracts/mocks/MerkleProofWrapper.sol
+++ b/contracts/mocks/MerkleProofWrapper.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import { MerkleProof } from "../cryptography/MerkleProof.sol";
 
diff --git a/contracts/mocks/OwnableMock.sol b/contracts/mocks/OwnableMock.sol
index 63562f50c..6508fc380 100644
--- a/contracts/mocks/OwnableMock.sol
+++ b/contracts/mocks/OwnableMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../access/Ownable.sol";
 
diff --git a/contracts/mocks/PausableMock.sol b/contracts/mocks/PausableMock.sol
index 827441dc3..a55f02c1e 100644
--- a/contracts/mocks/PausableMock.sol
+++ b/contracts/mocks/PausableMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../utils/Pausable.sol";
 
@@ -8,7 +8,7 @@ contract PausableMock is Pausable {
     bool public drasticMeasureTaken;
     uint256 public count;
 
-    constructor () public {
+    constructor () {
         drasticMeasureTaken = false;
         count = 0;
     }
diff --git a/contracts/mocks/PullPaymentMock.sol b/contracts/mocks/PullPaymentMock.sol
index aaaebf7f0..a97c67c16 100644
--- a/contracts/mocks/PullPaymentMock.sol
+++ b/contracts/mocks/PullPaymentMock.sol
@@ -1,12 +1,12 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../payment/PullPayment.sol";
 
 // mock class using PullPayment
 contract PullPaymentMock is PullPayment {
-    constructor () public payable { }
+    constructor () payable { }
 
     // test helper function to call asyncTransfer
     function callTransfer(address dest, uint256 amount) public {
diff --git a/contracts/mocks/ReentrancyAttack.sol b/contracts/mocks/ReentrancyAttack.sol
index b3fbde536..49cfea959 100644
--- a/contracts/mocks/ReentrancyAttack.sol
+++ b/contracts/mocks/ReentrancyAttack.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../GSN/Context.sol";
 contract ReentrancyAttack is Context {
diff --git a/contracts/mocks/ReentrancyMock.sol b/contracts/mocks/ReentrancyMock.sol
index 67610bb95..6a2422fad 100644
--- a/contracts/mocks/ReentrancyMock.sol
+++ b/contracts/mocks/ReentrancyMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../utils/ReentrancyGuard.sol";
 import "./ReentrancyAttack.sol";
@@ -8,7 +8,7 @@ import "./ReentrancyAttack.sol";
 contract ReentrancyMock is ReentrancyGuard {
     uint256 public counter;
 
-    constructor () public {
+    constructor () {
         counter = 0;
     }
 
diff --git a/contracts/mocks/SafeCastMock.sol b/contracts/mocks/SafeCastMock.sol
index cb953213d..03a11535b 100644
--- a/contracts/mocks/SafeCastMock.sol
+++ b/contracts/mocks/SafeCastMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../utils/SafeCast.sol";
 
diff --git a/contracts/mocks/SafeERC20Helper.sol b/contracts/mocks/SafeERC20Helper.sol
index d2dd31475..ab1bc1762 100644
--- a/contracts/mocks/SafeERC20Helper.sol
+++ b/contracts/mocks/SafeERC20Helper.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../GSN/Context.sol";
 import "../token/ERC20/IERC20.sol";
@@ -98,7 +98,7 @@ contract SafeERC20Wrapper is Context {
 
     IERC20 private _token;
 
-    constructor (IERC20 token) public {
+    constructor (IERC20 token) {
         _token = token;
     }
 
diff --git a/contracts/mocks/SafeMathMock.sol b/contracts/mocks/SafeMathMock.sol
index 0a07b3eba..2aa52effa 100644
--- a/contracts/mocks/SafeMathMock.sol
+++ b/contracts/mocks/SafeMathMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../math/SafeMath.sol";
 
diff --git a/contracts/mocks/SignedSafeMathMock.sol b/contracts/mocks/SignedSafeMathMock.sol
index 01c390764..1e482f1ea 100644
--- a/contracts/mocks/SignedSafeMathMock.sol
+++ b/contracts/mocks/SignedSafeMathMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../math/SignedSafeMath.sol";
 
diff --git a/contracts/mocks/StringsMock.sol b/contracts/mocks/StringsMock.sol
index 56963791b..0cc76b5b2 100644
--- a/contracts/mocks/StringsMock.sol
+++ b/contracts/mocks/StringsMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../utils/Strings.sol";
 
diff --git a/contracts/payment/PaymentSplitter.sol b/contracts/payment/PaymentSplitter.sol
index cba962181..e23df3530 100644
--- a/contracts/payment/PaymentSplitter.sol
+++ b/contracts/payment/PaymentSplitter.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../GSN/Context.sol";
 import "../math/SafeMath.sol";
@@ -39,7 +39,7 @@ contract PaymentSplitter is Context {
      * All addresses in `payees` must be non-zero. Both arrays must have the same non-zero length, and there must be no
      * duplicates in `payees`.
      */
-    constructor (address[] memory payees, uint256[] memory shares) public payable {
+    constructor (address[] memory payees, uint256[] memory shares) payable {
         // solhint-disable-next-line max-line-length
         require(payees.length == shares.length, "PaymentSplitter: payees and shares length mismatch");
         require(payees.length > 0, "PaymentSplitter: no payees");
diff --git a/contracts/payment/PullPayment.sol b/contracts/payment/PullPayment.sol
index 605edce65..251b09789 100644
--- a/contracts/payment/PullPayment.sol
+++ b/contracts/payment/PullPayment.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.2;
+pragma solidity ^0.7.0;
 
 import "./escrow/Escrow.sol";
 
@@ -25,7 +25,7 @@ import "./escrow/Escrow.sol";
 contract PullPayment {
     Escrow private _escrow;
 
-    constructor () internal {
+    constructor () {
         _escrow = new Escrow();
     }
 
diff --git a/contracts/payment/escrow/ConditionalEscrow.sol b/contracts/payment/escrow/ConditionalEscrow.sol
index 54bf17471..4aab43ad5 100644
--- a/contracts/payment/escrow/ConditionalEscrow.sol
+++ b/contracts/payment/escrow/ConditionalEscrow.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./Escrow.sol";
 
diff --git a/contracts/payment/escrow/Escrow.sol b/contracts/payment/escrow/Escrow.sol
index c9fc76e9f..fc85802ce 100644
--- a/contracts/payment/escrow/Escrow.sol
+++ b/contracts/payment/escrow/Escrow.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../../math/SafeMath.sol";
 import "../../access/Ownable.sol";
diff --git a/contracts/payment/escrow/RefundEscrow.sol b/contracts/payment/escrow/RefundEscrow.sol
index e581e7530..071084231 100644
--- a/contracts/payment/escrow/RefundEscrow.sol
+++ b/contracts/payment/escrow/RefundEscrow.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./ConditionalEscrow.sol";
 
@@ -27,7 +27,7 @@ contract RefundEscrow is ConditionalEscrow {
      * @dev Constructor.
      * @param beneficiary The beneficiary of the deposits.
      */
-    constructor (address payable beneficiary) public {
+    constructor (address payable beneficiary) {
         require(beneficiary != address(0), "RefundEscrow: beneficiary is the zero address");
         _beneficiary = beneficiary;
         _state = State.Active;
diff --git a/contracts/presets/ERC1155PresetMinterPauser.sol b/contracts/presets/ERC1155PresetMinterPauser.sol
index 078406ae5..1c9b02388 100644
--- a/contracts/presets/ERC1155PresetMinterPauser.sol
+++ b/contracts/presets/ERC1155PresetMinterPauser.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../access/AccessControl.sol";
 import "../GSN/Context.sol";
@@ -30,7 +30,7 @@ contract ERC1155PresetMinterPauser is Context, AccessControl, ERC1155Burnable, E
      * @dev Grants `DEFAULT_ADMIN_ROLE`, `MINTER_ROLE`, and `PAUSER_ROLE` to the account that
      * deploys the contract.
      */
-    constructor(string memory uri) public ERC1155(uri) {
+    constructor(string memory uri) ERC1155(uri) {
         _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
 
         _setupRole(MINTER_ROLE, _msgSender());
diff --git a/contracts/presets/ERC20PresetMinterPauser.sol b/contracts/presets/ERC20PresetMinterPauser.sol
index 00175955f..c0634ddde 100644
--- a/contracts/presets/ERC20PresetMinterPauser.sol
+++ b/contracts/presets/ERC20PresetMinterPauser.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../access/AccessControl.sol";
 import "../GSN/Context.sol";
@@ -32,7 +32,7 @@ contract ERC20PresetMinterPauser is Context, AccessControl, ERC20Burnable, ERC20
      *
      * See {ERC20-constructor}.
      */
-    constructor(string memory name, string memory symbol) public ERC20(name, symbol) {
+    constructor(string memory name, string memory symbol) ERC20(name, symbol) {
         _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
 
         _setupRole(MINTER_ROLE, _msgSender());
diff --git a/contracts/presets/ERC721PresetMinterPauserAutoId.sol b/contracts/presets/ERC721PresetMinterPauserAutoId.sol
index 9a9ce0dee..225ff9787 100644
--- a/contracts/presets/ERC721PresetMinterPauserAutoId.sol
+++ b/contracts/presets/ERC721PresetMinterPauserAutoId.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../access/AccessControl.sol";
 import "../GSN/Context.sol";
@@ -39,7 +39,7 @@ contract ERC721PresetMinterPauserAutoId is Context, AccessControl, ERC721Burnabl
      * Token URIs will be autogenerated based on `baseURI` and their token IDs.
      * See {ERC721-tokenURI}.
      */
-    constructor(string memory name, string memory symbol, string memory baseURI) public ERC721(name, symbol) {
+    constructor(string memory name, string memory symbol, string memory baseURI) ERC721(name, symbol) {
         _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
 
         _setupRole(MINTER_ROLE, _msgSender());
diff --git a/contracts/token/ERC1155/ERC1155.sol b/contracts/token/ERC1155/ERC1155.sol
index 2e39cbb42..2b8a34640 100644
--- a/contracts/token/ERC1155/ERC1155.sol
+++ b/contracts/token/ERC1155/ERC1155.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./IERC1155.sol";
 import "./IERC1155MetadataURI.sol";
@@ -52,7 +52,7 @@ contract ERC1155 is Context, ERC165, IERC1155, IERC1155MetadataURI {
     /**
      * @dev See {_setURI}.
      */
-    constructor (string memory uri) public {
+    constructor (string memory uri) {
         _setURI(uri);
 
         // register the supported interfaces to conform to ERC1155 via ERC165
diff --git a/contracts/token/ERC1155/ERC1155Burnable.sol b/contracts/token/ERC1155/ERC1155Burnable.sol
index 83edd4778..92a8b46e0 100644
--- a/contracts/token/ERC1155/ERC1155Burnable.sol
+++ b/contracts/token/ERC1155/ERC1155Burnable.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./ERC1155.sol";
 
diff --git a/contracts/token/ERC1155/ERC1155Holder.sol b/contracts/token/ERC1155/ERC1155Holder.sol
index 82d5979a3..647feb35b 100644
--- a/contracts/token/ERC1155/ERC1155Holder.sol
+++ b/contracts/token/ERC1155/ERC1155Holder.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./ERC1155Receiver.sol";
 
diff --git a/contracts/token/ERC1155/ERC1155Pausable.sol b/contracts/token/ERC1155/ERC1155Pausable.sol
index a2626cc5f..436bf1a24 100644
--- a/contracts/token/ERC1155/ERC1155Pausable.sol
+++ b/contracts/token/ERC1155/ERC1155Pausable.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./ERC1155.sol";
 import "../../utils/Pausable.sol";
diff --git a/contracts/token/ERC1155/ERC1155Receiver.sol b/contracts/token/ERC1155/ERC1155Receiver.sol
index 201660bce..d65eba872 100644
--- a/contracts/token/ERC1155/ERC1155Receiver.sol
+++ b/contracts/token/ERC1155/ERC1155Receiver.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./IERC1155Receiver.sol";
 import "../../introspection/ERC165.sol";
@@ -9,7 +9,7 @@ import "../../introspection/ERC165.sol";
  * @dev _Available since v3.1._
  */
 abstract contract ERC1155Receiver is ERC165, IERC1155Receiver {
-    constructor() public {
+    constructor() {
         _registerInterface(
             ERC1155Receiver(0).onERC1155Received.selector ^
             ERC1155Receiver(0).onERC1155BatchReceived.selector
diff --git a/contracts/token/ERC1155/IERC1155.sol b/contracts/token/ERC1155/IERC1155.sol
index be606beeb..30ebaf3b3 100644
--- a/contracts/token/ERC1155/IERC1155.sol
+++ b/contracts/token/ERC1155/IERC1155.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.2;
+pragma solidity ^0.7.0;
 
 import "../../introspection/IERC165.sol";
 
diff --git a/contracts/token/ERC1155/IERC1155MetadataURI.sol b/contracts/token/ERC1155/IERC1155MetadataURI.sol
index 2716c7708..c0b769e12 100644
--- a/contracts/token/ERC1155/IERC1155MetadataURI.sol
+++ b/contracts/token/ERC1155/IERC1155MetadataURI.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.2;
+pragma solidity ^0.7.0;
 
 import "./IERC1155.sol";
 
diff --git a/contracts/token/ERC1155/IERC1155Receiver.sol b/contracts/token/ERC1155/IERC1155Receiver.sol
index 6bd3dc2cf..f4bf40f0e 100644
--- a/contracts/token/ERC1155/IERC1155Receiver.sol
+++ b/contracts/token/ERC1155/IERC1155Receiver.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../../introspection/IERC165.sol";
 
diff --git a/contracts/token/ERC20/ERC20.sol b/contracts/token/ERC20/ERC20.sol
index a8ab97f27..799e99c1d 100644
--- a/contracts/token/ERC20/ERC20.sol
+++ b/contracts/token/ERC20/ERC20.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../../GSN/Context.sol";
 import "./IERC20.sol";
@@ -54,7 +54,7 @@ contract ERC20 is Context, IERC20 {
      * All three of these values are immutable: they can only be set once during
      * construction.
      */
-    constructor (string memory name, string memory symbol) public {
+    constructor (string memory name, string memory symbol) {
         _name = name;
         _symbol = symbol;
         _decimals = 18;
diff --git a/contracts/token/ERC20/ERC20Burnable.sol b/contracts/token/ERC20/ERC20Burnable.sol
index 2ce6bac09..f85bee46b 100644
--- a/contracts/token/ERC20/ERC20Burnable.sol
+++ b/contracts/token/ERC20/ERC20Burnable.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../../GSN/Context.sol";
 import "./ERC20.sol";
@@ -11,6 +11,8 @@ import "./ERC20.sol";
  * recognized off-chain (via event analysis).
  */
 abstract contract ERC20Burnable is Context, ERC20 {
+    using SafeMath for uint256;
+
     /**
      * @dev Destroys `amount` tokens from the caller.
      *
diff --git a/contracts/token/ERC20/ERC20Capped.sol b/contracts/token/ERC20/ERC20Capped.sol
index 3cff3b736..0dae5ae74 100644
--- a/contracts/token/ERC20/ERC20Capped.sol
+++ b/contracts/token/ERC20/ERC20Capped.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./ERC20.sol";
 
@@ -8,13 +8,15 @@ import "./ERC20.sol";
  * @dev Extension of {ERC20} that adds a cap to the supply of tokens.
  */
 abstract contract ERC20Capped is ERC20 {
+    using SafeMath for uint256;
+
     uint256 private _cap;
 
     /**
      * @dev Sets the value of the `cap`. This value is immutable, it can only be
      * set once during construction.
      */
-    constructor (uint256 cap) public {
+    constructor (uint256 cap) {
         require(cap > 0, "ERC20Capped: cap is 0");
         _cap = cap;
     }
diff --git a/contracts/token/ERC20/ERC20Pausable.sol b/contracts/token/ERC20/ERC20Pausable.sol
index a08b9df69..f7f0b70dc 100644
--- a/contracts/token/ERC20/ERC20Pausable.sol
+++ b/contracts/token/ERC20/ERC20Pausable.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./ERC20.sol";
 import "../../utils/Pausable.sol";
diff --git a/contracts/token/ERC20/ERC20Snapshot.sol b/contracts/token/ERC20/ERC20Snapshot.sol
index 54d91c057..34ef6d46c 100644
--- a/contracts/token/ERC20/ERC20Snapshot.sol
+++ b/contracts/token/ERC20/ERC20Snapshot.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../../math/SafeMath.sol";
 import "../../utils/Arrays.sol";
diff --git a/contracts/token/ERC20/IERC20.sol b/contracts/token/ERC20/IERC20.sol
index a1f9ca7f6..935dd17e8 100644
--- a/contracts/token/ERC20/IERC20.sol
+++ b/contracts/token/ERC20/IERC20.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Interface of the ERC20 standard as defined in the EIP.
diff --git a/contracts/token/ERC20/SafeERC20.sol b/contracts/token/ERC20/SafeERC20.sol
index e5f0d23aa..d048b8e52 100644
--- a/contracts/token/ERC20/SafeERC20.sol
+++ b/contracts/token/ERC20/SafeERC20.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./IERC20.sol";
 import "../../math/SafeMath.sol";
diff --git a/contracts/token/ERC20/TokenTimelock.sol b/contracts/token/ERC20/TokenTimelock.sol
index 0d05ed82c..cecaff579 100644
--- a/contracts/token/ERC20/TokenTimelock.sol
+++ b/contracts/token/ERC20/TokenTimelock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./SafeERC20.sol";
 
@@ -23,7 +23,7 @@ contract TokenTimelock {
     // timestamp when token release is enabled
     uint256 private _releaseTime;
 
-    constructor (IERC20 token, address beneficiary, uint256 releaseTime) public {
+    constructor (IERC20 token, address beneficiary, uint256 releaseTime) {
         // solhint-disable-next-line not-rely-on-time
         require(releaseTime > block.timestamp, "TokenTimelock: release time is before current time");
         _token = token;
diff --git a/contracts/token/ERC721/ERC721.sol b/contracts/token/ERC721/ERC721.sol
index 6094c1531..a46b1126a 100644
--- a/contracts/token/ERC721/ERC721.sol
+++ b/contracts/token/ERC721/ERC721.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../../GSN/Context.sol";
 import "./IERC721.sol";
@@ -90,7 +90,7 @@ contract ERC721 is Context, ERC165, IERC721, IERC721Metadata, IERC721Enumerable
     /**
      * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
      */
-    constructor (string memory name, string memory symbol) public {
+    constructor (string memory name, string memory symbol) {
         _name = name;
         _symbol = symbol;
 
diff --git a/contracts/token/ERC721/ERC721Burnable.sol b/contracts/token/ERC721/ERC721Burnable.sol
index 6f767d23a..2bb3042ba 100644
--- a/contracts/token/ERC721/ERC721Burnable.sol
+++ b/contracts/token/ERC721/ERC721Burnable.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../../GSN/Context.sol";
 import "./ERC721.sol";
diff --git a/contracts/token/ERC721/ERC721Holder.sol b/contracts/token/ERC721/ERC721Holder.sol
index 3684bd1cc..aea1fddaa 100644
--- a/contracts/token/ERC721/ERC721Holder.sol
+++ b/contracts/token/ERC721/ERC721Holder.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./IERC721Receiver.sol";
 
diff --git a/contracts/token/ERC721/ERC721Pausable.sol b/contracts/token/ERC721/ERC721Pausable.sol
index c59064743..d5aa0c7dc 100644
--- a/contracts/token/ERC721/ERC721Pausable.sol
+++ b/contracts/token/ERC721/ERC721Pausable.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "./ERC721.sol";
 import "../../utils/Pausable.sol";
diff --git a/contracts/token/ERC721/IERC721.sol b/contracts/token/ERC721/IERC721.sol
index 16f7aca87..deea646e3 100644
--- a/contracts/token/ERC721/IERC721.sol
+++ b/contracts/token/ERC721/IERC721.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.2;
+pragma solidity ^0.7.0;
 
 import "../../introspection/IERC165.sol";
 
diff --git a/contracts/token/ERC721/IERC721Enumerable.sol b/contracts/token/ERC721/IERC721Enumerable.sol
index bd3c86d18..94a3efa4a 100644
--- a/contracts/token/ERC721/IERC721Enumerable.sol
+++ b/contracts/token/ERC721/IERC721Enumerable.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.2;
+pragma solidity ^0.7.0;
 
 import "./IERC721.sol";
 
diff --git a/contracts/token/ERC721/IERC721Metadata.sol b/contracts/token/ERC721/IERC721Metadata.sol
index f2ebb4955..a5480854c 100644
--- a/contracts/token/ERC721/IERC721Metadata.sol
+++ b/contracts/token/ERC721/IERC721Metadata.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.2;
+pragma solidity ^0.7.0;
 
 import "./IERC721.sol";
 
diff --git a/contracts/token/ERC721/IERC721Receiver.sol b/contracts/token/ERC721/IERC721Receiver.sol
index f98053e59..a0edf5cc8 100644
--- a/contracts/token/ERC721/IERC721Receiver.sol
+++ b/contracts/token/ERC721/IERC721Receiver.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @title ERC721 token receiver interface
diff --git a/contracts/token/ERC777/ERC777.sol b/contracts/token/ERC777/ERC777.sol
index 5adb8ff0d..42098edcd 100644
--- a/contracts/token/ERC777/ERC777.sol
+++ b/contracts/token/ERC777/ERC777.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../../GSN/Context.sol";
 import "./IERC777.sol";
@@ -70,7 +70,7 @@ contract ERC777 is Context, IERC777, IERC20 {
         string memory name,
         string memory symbol,
         address[] memory defaultOperators
-    ) public {
+    ) {
         _name = name;
         _symbol = symbol;
 
diff --git a/contracts/token/ERC777/IERC777.sol b/contracts/token/ERC777/IERC777.sol
index f3dcbe93c..b37c564da 100644
--- a/contracts/token/ERC777/IERC777.sol
+++ b/contracts/token/ERC777/IERC777.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Interface of the ERC777Token standard as defined in the EIP.
diff --git a/contracts/token/ERC777/IERC777Recipient.sol b/contracts/token/ERC777/IERC777Recipient.sol
index 179ed6626..e610996b0 100644
--- a/contracts/token/ERC777/IERC777Recipient.sol
+++ b/contracts/token/ERC777/IERC777Recipient.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Interface of the ERC777TokensRecipient standard as defined in the EIP.
diff --git a/contracts/token/ERC777/IERC777Sender.sol b/contracts/token/ERC777/IERC777Sender.sol
index 841ca208f..31190d0c6 100644
--- a/contracts/token/ERC777/IERC777Sender.sol
+++ b/contracts/token/ERC777/IERC777Sender.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Interface of the ERC777TokensSender standard as defined in the EIP.
diff --git a/contracts/utils/Address.sol b/contracts/utils/Address.sol
index fe3ba6537..23a4589c6 100644
--- a/contracts/utils/Address.sol
+++ b/contracts/utils/Address.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.2;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Collection of functions related to the address type
diff --git a/contracts/utils/Arrays.sol b/contracts/utils/Arrays.sol
index 8d586e9e9..65402827a 100644
--- a/contracts/utils/Arrays.sol
+++ b/contracts/utils/Arrays.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../math/Math.sol";
 
diff --git a/contracts/utils/Counters.sol b/contracts/utils/Counters.sol
index 82cb62bfd..c424816d4 100644
--- a/contracts/utils/Counters.sol
+++ b/contracts/utils/Counters.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../math/SafeMath.sol";
 
diff --git a/contracts/utils/Create2.sol b/contracts/utils/Create2.sol
index 8f9efa10b..b5923228c 100644
--- a/contracts/utils/Create2.sol
+++ b/contracts/utils/Create2.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Helper to make usage of the `CREATE2` EVM opcode easier and safer.
diff --git a/contracts/utils/EnumerableMap.sol b/contracts/utils/EnumerableMap.sol
index 82eb04c9c..0124c78b0 100644
--- a/contracts/utils/EnumerableMap.sol
+++ b/contracts/utils/EnumerableMap.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Library for managing an enumerable variant of Solidity's
diff --git a/contracts/utils/EnumerableSet.sol b/contracts/utils/EnumerableSet.sol
index 7f4c761ab..a0f8680c4 100644
--- a/contracts/utils/EnumerableSet.sol
+++ b/contracts/utils/EnumerableSet.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Library for managing
diff --git a/contracts/utils/Pausable.sol b/contracts/utils/Pausable.sol
index 9e1b42ab7..70399c9f3 100644
--- a/contracts/utils/Pausable.sol
+++ b/contracts/utils/Pausable.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "../GSN/Context.sol";
 
@@ -29,7 +29,7 @@ contract Pausable is Context {
     /**
      * @dev Initializes the contract in unpaused state.
      */
-    constructor () internal {
+    constructor () {
         _paused = false;
     }
 
diff --git a/contracts/utils/ReentrancyGuard.sol b/contracts/utils/ReentrancyGuard.sol
index b7bea91f8..7e9c3cb80 100644
--- a/contracts/utils/ReentrancyGuard.sol
+++ b/contracts/utils/ReentrancyGuard.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev Contract module that helps prevent reentrant calls to a function.
@@ -35,7 +35,7 @@ contract ReentrancyGuard {
 
     uint256 private _status;
 
-    constructor () internal {
+    constructor () {
         _status = _NOT_ENTERED;
     }
 
diff --git a/contracts/utils/SafeCast.sol b/contracts/utils/SafeCast.sol
index 9d283ff25..1e8355e28 100644
--- a/contracts/utils/SafeCast.sol
+++ b/contracts/utils/SafeCast.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 
 /**
diff --git a/contracts/utils/Strings.sol b/contracts/utils/Strings.sol
index aacce819c..5177785ef 100644
--- a/contracts/utils/Strings.sol
+++ b/contracts/utils/Strings.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 /**
  * @dev String operations.
diff --git a/docs/modules/ROOT/pages/access-control.adoc b/docs/modules/ROOT/pages/access-control.adoc
index 20ac4cf03..baab7ee15 100644
--- a/docs/modules/ROOT/pages/access-control.adoc
+++ b/docs/modules/ROOT/pages/access-control.adoc
@@ -13,7 +13,7 @@ OpenZeppelin provides xref:api:access.adoc#Ownable[`Ownable`] for implementing o
 ----
 // contracts/MyContract.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/access/Ownable.sol";
 
@@ -62,7 +62,7 @@ Here's a simple example of using `AccessControl` in an xref:tokens.adoc#ERC20[`E
 ----
 // contracts/MyToken.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/access/AccessControl.sol";
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
@@ -71,7 +71,7 @@ contract MyToken is ERC20, AccessControl {
     // Create a new role identifier for the minter role
     bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
 
-    constructor(address minter) public ERC20("MyToken", "TKN") {
+    constructor(address minter) ERC20("MyToken", "TKN") {
         // Grant the minter role to a specified account
         _setupRole(MINTER_ROLE, minter);
     }
@@ -94,7 +94,7 @@ Let's augment our ERC20 token example by also defining a 'burner' role, which le
 ----
 // contracts/MyToken.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/access/AccessControl.sol";
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
@@ -103,7 +103,7 @@ contract MyToken is ERC20, AccessControl {
     bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
     bytes32 public constant BURNER_ROLE = keccak256("BURNER_ROLE");
 
-    constructor(address minter, address burner) public ERC20("MyToken", "TKN") {
+    constructor(address minter, address burner) ERC20("MyToken", "TKN") {
         _setupRole(MINTER_ROLE, minter);
         _setupRole(BURNER_ROLE, burner);
     }
@@ -139,7 +139,7 @@ Let's take a look at the ERC20 token example, this time taking advantage of the
 ----
 // contracts/MyToken.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/access/AccessControl.sol";
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
@@ -148,7 +148,7 @@ contract MyToken is ERC20, AccessControl {
     bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
     bytes32 public constant BURNER_ROLE = keccak256("BURNER_ROLE");
 
-    constructor() public ERC20("MyToken", "TKN") {
+    constructor() ERC20("MyToken", "TKN") {
         // Grant the contract deployer the default admin role: it will be able
         // to grant and revoke any roles
         _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
diff --git a/docs/modules/ROOT/pages/erc1155.adoc b/docs/modules/ROOT/pages/erc1155.adoc
index f00dd499b..48b0650e4 100644
--- a/docs/modules/ROOT/pages/erc1155.adoc
+++ b/docs/modules/ROOT/pages/erc1155.adoc
@@ -34,7 +34,7 @@ Here's what a contract for tokenized items might look like:
 ----
 // contracts/GameItems.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/token/ERC1155/ERC1155.sol";
 
@@ -45,7 +45,7 @@ contract GameItems is ERC1155 {
     uint256 public constant SWORD = 3;
     uint256 public constant SHIELD = 4;
 
-    constructor() public ERC1155("https://game.example/api/item/{1}.json") {
+    constructor() ERC1155("https://game.example/api/item/{1}.json") {
         _mint(msg.sender, GOLD, 10**18, "");
         _mint(msg.sender, SILVER, 10**27, "");
         _mint(msg.sender, THORS_HAMMER, 1, "");
@@ -132,7 +132,7 @@ In order for our contract to receive ERC1155 tokens we can inherit from the conv
 ----
 // contracts/MyContract.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/token/ERC1155/ERC1155Holder.sol";
 
diff --git a/docs/modules/ROOT/pages/erc20-supply.adoc b/docs/modules/ROOT/pages/erc20-supply.adoc
index 3db0828d8..84830615d 100644
--- a/docs/modules/ROOT/pages/erc20-supply.adoc
+++ b/docs/modules/ROOT/pages/erc20-supply.adoc
@@ -14,7 +14,7 @@ Let's say we want a token with a fixed supply of 1000, initially allocated to th
 [source,solidity]
 ----
 contract ERC20FixedSupply is ERC20 {
-    constructor() public {
+    constructor() {
         totalSupply += 1000;
         balances[msg.sender] += 1000;
     }
@@ -26,7 +26,7 @@ Starting with Contracts v2 this pattern is not only discouraged, but disallowed.
 [source,solidity]
 ----
 contract ERC20FixedSupply is ERC20 {
-    constructor() public ERC20("Fixed", "FIX") {
+    constructor() ERC20("Fixed", "FIX") {
         _mint(msg.sender, 1000);
     }
 }
@@ -44,7 +44,7 @@ The mechanism we will implement is a token reward for the miners that produce Et
 [source,solidity]
 ----
 contract ERC20WithMinerReward is ERC20 {
-    constructor() public ERC20("Reward", "RWD") {}
+    constructor() ERC20("Reward", "RWD") {}
 
     function mintMinerReward() public {
         _mint(block.coinbase, 1000);
@@ -68,7 +68,7 @@ The accounts with the minter role don't need to be externally owned, though, and
 contract MinerRewardMinter {
     ERC20PresetMinterPauser _token;
 
-    constructor(ERC20PresetMinterPauser token) public {
+    constructor(ERC20PresetMinterPauser token) {
         _token = token;
     }
 
@@ -92,7 +92,7 @@ Adding to the supply mechanism from previous sections, we can use this hook to m
 [source,solidity]
 ----
 contract ERC20WithAutoMinerReward is ERC20 {
-    constructor() public ERC20("Reward", "RWD") {}
+    constructor() ERC20("Reward", "RWD") {}
 
     function _mintMinerReward() internal {
         _mint(block.coinbase, 1000);
diff --git a/docs/modules/ROOT/pages/erc20.adoc b/docs/modules/ROOT/pages/erc20.adoc
index 7a132019a..3f8e579cc 100644
--- a/docs/modules/ROOT/pages/erc20.adoc
+++ b/docs/modules/ROOT/pages/erc20.adoc
@@ -15,12 +15,12 @@ Here's what our GLD token might look like.
 ----
 // contracts/GLDToken.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 
 contract GLDToken is ERC20 {
-    constructor(uint256 initialSupply) public ERC20("Gold", "GLD") {
+    constructor(uint256 initialSupply) ERC20("Gold", "GLD") {
         _mint(msg.sender, initialSupply);
     }
 }
diff --git a/docs/modules/ROOT/pages/erc721.adoc b/docs/modules/ROOT/pages/erc721.adoc
index 005ed3f76..ef322a9ab 100644
--- a/docs/modules/ROOT/pages/erc721.adoc
+++ b/docs/modules/ROOT/pages/erc721.adoc
@@ -14,7 +14,7 @@ Here's what a contract for tokenized items might look like:
 ----
 // contracts/GameItem.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
 import "@openzeppelin/contracts/utils/Counters.sol";
@@ -23,7 +23,7 @@ contract GameItem is ERC721 {
     using Counters for Counters.Counter;
     Counters.Counter private _tokenIds;
 
-    constructor() public ERC721("GameItem", "ITM") {}
+    constructor() ERC721("GameItem", "ITM") {}
 
     function awardItem(address player, string memory tokenURI)
         public
diff --git a/docs/modules/ROOT/pages/erc777.adoc b/docs/modules/ROOT/pages/erc777.adoc
index 7d69ca011..741afac1f 100644
--- a/docs/modules/ROOT/pages/erc777.adoc
+++ b/docs/modules/ROOT/pages/erc777.adoc
@@ -20,13 +20,12 @@ We will replicate the `GLD` example of the xref:erc20.adoc#constructing-an-erc20
 ----
 // contracts/GLDToken.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/token/ERC777/ERC777.sol";
 
 contract GLDToken is ERC777 {
     constructor(uint256 initialSupply, address[] memory defaultOperators)
-        public
         ERC777("Gold", "GLD", defaultOperators)
     {
         _mint(msg.sender, initialSupply, "", "");
diff --git a/docs/modules/ROOT/pages/extending-contracts.adoc b/docs/modules/ROOT/pages/extending-contracts.adoc
index a97e2e45b..bbbb1ab0a 100644
--- a/docs/modules/ROOT/pages/extending-contracts.adoc
+++ b/docs/modules/ROOT/pages/extending-contracts.adoc
@@ -20,7 +20,7 @@ For example, imagine you want to change xref:api:access.adoc#AccessControl[`Acce
 ```solidity
 // contracts/ModifiedAccessControl.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/access/AccessControl.sol";
 
@@ -48,7 +48,7 @@ Here is a modified version of xref:api:access.adoc#AccessControl[`AccessControl`
 ```solidity
 // contracts/ModifiedAccessControl.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/access/AccessControl.sol";
 
@@ -80,7 +80,7 @@ Hooks are simply functions that are called before or after some action takes pla
 Here's how you would implement the `IERC721Receiver` pattern in `ERC20`, using the xref:api:token/ERC20.adoc#ERC20-_beforeTokenTransfer-address-address-uint256-[`_beforeTokenTransfer`] hook:
 
 ```solidity
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 
diff --git a/docs/modules/ROOT/pages/gsn-strategies.adoc b/docs/modules/ROOT/pages/gsn-strategies.adoc
index 1a7543d62..0771e4d1d 100644
--- a/docs/modules/ROOT/pages/gsn-strategies.adoc
+++ b/docs/modules/ROOT/pages/gsn-strategies.adoc
@@ -62,7 +62,7 @@ Instead of using `GSNRecipient` directly, your GSN recipient contract will inste
 import "@openzeppelin/contracts/GSN/GSNRecipientSignature.sol";
 
 contract MyContract is GSNRecipientSignature {
-    constructor(address trustedSigner) public GSNRecipientSignature(trustedSigner) {
+    constructor(address trustedSigner) GSNRecipientSignature(trustedSigner) {
     }
 }
 ----
@@ -108,7 +108,7 @@ Your GSN recipient contract needs to inherit from `GSNRecipientERC20Fee` along w
 ----
 // contracts/MyContract.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/GSN/GSNRecipientERC20Fee.sol";
 import "@openzeppelin/contracts/access/AccessControl.sol";
@@ -116,7 +116,7 @@ import "@openzeppelin/contracts/access/AccessControl.sol";
 contract MyContract is GSNRecipientERC20Fee, AccessControl {
     bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
 
-    constructor() public GSNRecipientERC20Fee("FeeToken", "FEE") {
+    constructor() GSNRecipientERC20Fee("FeeToken", "FEE") {
         _setupRole(MINTER_ROLE, _msgSender());
     }
 
@@ -154,7 +154,7 @@ Once your strategy is ready, all your GSN recipient needs to do is inherit from
 [source,solidity]
 ----
 contract MyContract is MyCustomGSNStrategy {
-    constructor() public MyCustomGSNStrategy() {
+    constructor() MyCustomGSNStrategy() {
     }
 }
 ----
diff --git a/docs/modules/ROOT/pages/index.adoc b/docs/modules/ROOT/pages/index.adoc
index b43cbe086..29c3763d5 100644
--- a/docs/modules/ROOT/pages/index.adoc
+++ b/docs/modules/ROOT/pages/index.adoc
@@ -28,12 +28,12 @@ Once installed, you can use the contracts in the library by importing them:
 ----
 // contracts/MyNFT.sol
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.6.0;
+pragma solidity ^0.7.0;
 
 import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
 
 contract MyNFT is ERC721 {
-    constructor() ERC721("MyNFT", "MNFT") public {
+    constructor() ERC721("MyNFT", "MNFT") {
     }
 }
 ----