diff --git a/contracts/apps/disputable/IAgreement.sol b/contracts/apps/disputable/IAgreement.sol
index 333cb7a58..c91b56f63 100644
--- a/contracts/apps/disputable/IAgreement.sol
+++ b/contracts/apps/disputable/IAgreement.sol
@@ -7,6 +7,7 @@ pragma solidity ^0.4.24;
 import "../../acl/IACLOracle.sol";
 import "../../lib/token/ERC20.sol";
 import "../../lib/arbitration/IArbitrable.sol";
+import "../../lib/arbitration/ITransactionFeesOracle.sol";
 
 
 contract IAgreement is IArbitrable, IACLOracle {
@@ -61,7 +62,13 @@ contract IAgreement is IArbitrable, IACLOracle {
 
     function getCurrentSettingId() external view returns (uint256);
 
-    function getSetting(uint256 _settingId) external view returns (IArbitrator arbitrator, string title, bytes content);
+    function getSetting(uint256 _settingId) external view
+        returns (
+            IArbitrator arbitrator,
+            ITransactionFeesOracle transactionFeesOracle,
+            string title,
+            bytes content
+        );
 
     function getDisputableInfo(address _disputable) external view returns (bool registered, uint256 currentCollateralRequirementId);
 
diff --git a/contracts/apps/disputable/IDisputable.sol b/contracts/apps/disputable/IDisputable.sol
index 30e8ce783..f015feb67 100644
--- a/contracts/apps/disputable/IDisputable.sol
+++ b/contracts/apps/disputable/IDisputable.sol
@@ -11,7 +11,7 @@ import "../../lib/standards/ERC165.sol";
 
 contract IDisputable is ERC165 {
     bytes4 internal constant ERC165_INTERFACE_ID = bytes4(0x01ffc9a7);
-    bytes4 internal constant DISPUTABLE_INTERFACE_ID = bytes4(0xef113021);
+    bytes4 internal constant DISPUTABLE_INTERFACE_ID = bytes4(0x737c65f9);
 
     event AgreementSet(IAgreement indexed agreement);
 
@@ -39,4 +39,6 @@ contract IDisputable is ERC165 {
     function supportsInterface(bytes4 _interfaceId) external pure returns (bool) {
         return _interfaceId == DISPUTABLE_INTERFACE_ID || _interfaceId == ERC165_INTERFACE_ID;
     }
+
+    function appId() public view returns (bytes32);
 }
diff --git a/contracts/lib/arbitration/ITransactionFeesOracle.sol b/contracts/lib/arbitration/ITransactionFeesOracle.sol
new file mode 100644
index 000000000..df0cd3bbf
--- /dev/null
+++ b/contracts/lib/arbitration/ITransactionFeesOracle.sol
@@ -0,0 +1,12 @@
+pragma solidity ^0.4.24;
+
+import "../token/ERC20.sol";
+
+
+interface ITransactionFeesOracle {
+    function setFee(bytes32 appId, ERC20 token, uint256 amount) external;
+    function setFees(bytes32[] _appIds, ERC20[] _tokens, uint256[] _amounts) external;
+    function unsetFee(bytes32 _appId) external;
+    function unsetFees(bytes32[] _appIds) external;
+    function getFee(bytes32 appId) external view returns (ERC20, uint256, address);
+}
diff --git a/contracts/test/mocks/apps/disputable/DisputableAppMock.sol b/contracts/test/mocks/apps/disputable/DisputableAppMock.sol
index 42b893a64..4e8d10ba1 100644
--- a/contracts/test/mocks/apps/disputable/DisputableAppMock.sol
+++ b/contracts/test/mocks/apps/disputable/DisputableAppMock.sol
@@ -36,11 +36,14 @@ contract DisputableAppMock is DisputableAragonApp {
     function interfaceID() external pure returns (bytes4) {
         IDisputable iDisputable;
         return iDisputable.setAgreement.selector ^
-        iDisputable.onDisputableActionChallenged.selector ^
-        iDisputable.onDisputableActionAllowed.selector ^
-        iDisputable.onDisputableActionRejected.selector ^
-        iDisputable.onDisputableActionVoided.selector ^
-        iDisputable.getAgreement.selector;
+            iDisputable.onDisputableActionChallenged.selector ^
+            iDisputable.onDisputableActionAllowed.selector ^
+            iDisputable.onDisputableActionRejected.selector ^
+            iDisputable.onDisputableActionVoided.selector ^
+            iDisputable.getAgreement.selector ^
+            iDisputable.canChallenge.selector ^
+            iDisputable.canClose.selector ^
+            iDisputable.appId.selector;
     }
 
     function erc165interfaceID() external pure returns (bytes4) {
diff --git a/package.json b/package.json
index 53449adaf..4d6c9c091 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@aragon/os",
-  "version": "5.0.0-beta.0",
+  "version": "5.0.0-beta.1",
   "description": "Core contracts for Aragon",
   "scripts": {
     "compile": "truffle compile",
diff --git a/test/contracts/apps/disputable/disputable_app.js b/test/contracts/apps/disputable/disputable_app.js
index 84f3f903e..4f08896b9 100644
--- a/test/contracts/apps/disputable/disputable_app.js
+++ b/test/contracts/apps/disputable/disputable_app.js
@@ -14,6 +14,8 @@ contract('DisputableApp', ([_, owner, agreement, anotherAgreement, someone]) =>
   let disputable, disputableBase, dao, acl
 
   const ZERO_ADDRESS = '0x0000000000000000000000000000000000000000'
+  const DISPUTABLE_INTERFACE = '0x737c65f9'
+  const ERC165_INTERFACE = '0x01ffc9a7'
 
   before('deploy DAO', async () => {
     const kernelBase = await Kernel.new(true)
@@ -41,16 +43,16 @@ contract('DisputableApp', ([_, owner, agreement, anotherAgreement, someone]) =>
 
   describe('supportsInterface', () => {
     it('supports ERC165', async () => {
-      assert.isTrue(await disputable.supportsInterface('0x01ffc9a7'), 'does not support ERC165')
+      assert.isTrue(await disputable.supportsInterface(ERC165_INTERFACE), 'does not support ERC165')
 
-      assert.equal(await disputable.ERC165_INTERFACE(), '0x01ffc9a7', 'ERC165 interface ID does not match')
+      assert.equal(await disputable.ERC165_INTERFACE(), ERC165_INTERFACE, 'ERC165 interface ID does not match')
       assert.equal(await disputable.erc165interfaceID(), await disputable.ERC165_INTERFACE(), 'ERC165 interface ID does not match')
     })
 
     it('supports IDisputable', async () => {
-      assert.isTrue(await disputable.supportsInterface('0xef113021'), 'does not support IDisputable')
+      assert.isTrue(await disputable.supportsInterface(DISPUTABLE_INTERFACE), 'does not support IDisputable')
 
-      assert.equal(await disputable.interfaceID(), '0xef113021')
+      assert.equal(await disputable.interfaceID(), DISPUTABLE_INTERFACE)
       assert.equal(await disputable.DISPUTABLE_INTERFACE(), await disputable.interfaceID(), 'IDisputable interface ID does not match')
     })