diff --git a/contracts/impls/WitnetRequestBoardUpgradableBase.sol b/contracts/impls/WitnetRequestBoardUpgradableBase.sol
index fb22b414f..f55685843 100644
--- a/contracts/impls/WitnetRequestBoardUpgradableBase.sol
+++ b/contracts/impls/WitnetRequestBoardUpgradableBase.sol
@@ -17,7 +17,6 @@ import "./WitnetProxy.sol";
 /// @author The Witnet Foundation.
 abstract contract WitnetRequestBoardUpgradableBase
     is
-        Proxiable,
         Upgradable,
         WitnetRequestBoard
 {
diff --git a/contracts/impls/trustable/WitnetRequestBoardTrustableBoba.sol b/contracts/impls/trustable/WitnetRequestBoardTrustableBoba.sol
index da19ba51b..73f552605 100644
--- a/contracts/impls/trustable/WitnetRequestBoardTrustableBoba.sol
+++ b/contracts/impls/trustable/WitnetRequestBoardTrustableBoba.sol
@@ -18,8 +18,7 @@ import "../../interfaces/IERC20.sol";
 /// @author The Witnet Foundation
 contract WitnetRequestBoardTrustableBoba
     is
-        Payable,
-        WitnetRequestBoardTrustableBase
+    WitnetRequestBoardTrustableBase
 {
     uint256 internal lastBalance;
     uint256 internal immutable _OVM_GAS_PRICE;