diff --git a/contracts/common/DepositableDelegateProxy.sol b/contracts/common/DepositableDelegateProxy.sol
index adcc17f75..6b1049fed 100644
--- a/contracts/common/DepositableDelegateProxy.sol
+++ b/contracts/common/DepositableDelegateProxy.sol
@@ -6,7 +6,7 @@ import "./DelegateProxy.sol";
 contract DepositableDelegateProxy is DelegateProxy {
     event ProxyDeposit(address sender, uint256 value);
 
-    function () payable public {
+    function () external payable {
         // send / transfer
         if (msg.gas < FWD_GAS_LIMIT) {
             require(msg.value > 0 && msg.data.length == 0);
diff --git a/contracts/lib/minime/MiniMeToken.sol b/contracts/lib/minime/MiniMeToken.sol
index a6cfec1b1..527c0b4d5 100644
--- a/contracts/lib/minime/MiniMeToken.sol
+++ b/contracts/lib/minime/MiniMeToken.sol
@@ -493,7 +493,7 @@ contract MiniMeToken is Controlled {
     /// @notice The fallback function: If the contract's controller has not been
     ///  set to 0, then the `proxyPayment` method is called which relays the
     ///  ether and creates tokens as described in the token controller contract
-    function ()  payable  public {
+    function () external payable {
         require(isContract(controller));
         // Adding the ` == true` makes the linter shut up so...
         require(ITokenController(controller).proxyPayment.value(msg.value)(msg.sender) == true);
diff --git a/test/mocks/EncodeMock.sol b/test/mocks/EncodeMock.sol
index 4da1dea2c..86693f8ec 100644
--- a/test/mocks/EncodeMock.sol
+++ b/test/mocks/EncodeMock.sol
@@ -11,7 +11,7 @@ contract EncodeMock {
         EncodeMockInterface(this).gogo(a, b, c);
     }
 
-    function () public {
+    function () external {
         result = msg.data;
     }
 }
diff --git a/test/mocks/VaultMock.sol b/test/mocks/VaultMock.sol
index 3a5a553e3..d06ba3e9d 100644
--- a/test/mocks/VaultMock.sol
+++ b/test/mocks/VaultMock.sol
@@ -4,7 +4,7 @@ pragma solidity 0.4.18;
 contract VaultMock {
     event LogFund(address sender, uint256 amount);
 
-    function () public payable {
+    function () external payable {
         LogFund(msg.sender, msg.value);
     }
 }