diff --git a/l1-contracts/src/core/Leonidas.sol b/l1-contracts/src/core/Leonidas.sol
index eaca4ce3fa4..55b86818bc5 100644
--- a/l1-contracts/src/core/Leonidas.sol
+++ b/l1-contracts/src/core/Leonidas.sol
@@ -386,6 +386,7 @@ contract Leonidas is Ownable, ILeonidas {
     Timestamp ts = getTimestampForSlot(_slot);
     address proposer = getProposerAt(ts);
 
+    // @todo Consider getting rid of this option.
     // If the proposer is open, we allow anyone to propose without needing any signatures
     if (proposer == address(0)) {
       return;
diff --git a/l1-contracts/test/governance/scenario/UpgradeGerousia.t.sol b/l1-contracts/test/governance/scenario/UpgradeGerousia.t.sol
new file mode 100644
index 00000000000..b10b5b2cc0e
--- /dev/null
+++ b/l1-contracts/test/governance/scenario/UpgradeGerousia.t.sol
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity >=0.8.27;
+
+import {IPayload} from "@aztec/governance/interfaces/IPayload.sol";
+import {TestBase} from "@test/base/Base.sol";
+import {IMintableERC20} from "@aztec/governance/interfaces/IMintableERC20.sol";
+import {IRegistry} from "@aztec/governance/interfaces/IRegistry.sol";
+import {Rollup} from "@aztec/core/Rollup.sol";
+import {Apella} from "@aztec/governance/Apella.sol";
+import {Gerousia} from "@aztec/governance/Gerousia.sol";
+import {Registry} from "@aztec/governance/Registry.sol";
+import {DataStructures} from "@aztec/governance/libraries/DataStructures.sol";
+import {IMintableERC20} from "@aztec/governance/interfaces/IMintableERC20.sol";
+import {TestERC20} from "@aztec/mock/TestERC20.sol";
+import {Timestamp} from "@aztec/core/libraries/TimeMath.sol";
+import {MockFeeJuicePortal} from "@aztec/mock/MockFeeJuicePortal.sol";
+import {Slot} from "@aztec/core/libraries/TimeMath.sol";
+import {ProposalLib} from "@aztec/governance/libraries/ProposalLib.sol";
+import {Errors} from "@aztec/governance/libraries/Errors.sol";
+
+/**
+ * @title NewGerousiaPayload
+ * @author Aztec Labs
+ * @notice A payload that upgrades the Gerousia contract to a new version.
+ */
+contract NewGerousiaPayload is IPayload {
+  IRegistry public immutable REGISTRY;
+  address public immutable NEW_GEROUSIA;
+
+  constructor(IRegistry _registry) {
+    REGISTRY = _registry;
+    NEW_GEROUSIA = address(new Gerousia(_registry, 667, 1000));
+  }
+
+  function getActions() external view override(IPayload) returns (IPayload.Action[] memory) {
+    IPayload.Action[] memory res = new IPayload.Action[](1);
+
+    Apella apella = Apella(REGISTRY.getApella());
+
+    res[0] = Action({
+      target: address(apella),
+      data: abi.encodeWithSelector(apella.updateGerousia.selector, NEW_GEROUSIA)
+    });
+
+    return res;
+  }
+}
+
+/**
+ * @title UpgradeGerousiaTest
+ * @author Aztec Labs
+ * @notice A test that showcases an upgrade of the governance system, here the gerousia contract.
+ */
+contract UpgradeGerousiaTest is TestBase {
+  using ProposalLib for DataStructures.Proposal;
+
+  IMintableERC20 internal token;
+  Registry internal registry;
+  Apella internal apella;
+  Gerousia internal gerousia;
+  Rollup internal rollup;
+
+  DataStructures.Proposal internal proposal;
+
+  mapping(uint256 => address) internal validators;
+  mapping(address validator => uint256 privateKey) internal privateKeys;
+
+  IPayload internal payload;
+
+  uint256 internal constant VALIDATOR_COUNT = 4;
+  address internal constant EMPEROR = address(uint160(bytes20("EMPEROR")));
+
+  function setUp() external {
+    token = IMintableERC20(address(new TestERC20()));
+
+    registry = new Registry(address(this));
+    gerousia = new Gerousia(registry, 7, 10);
+
+    apella = new Apella(token, address(gerousia));
+
+    address[] memory initialValidators = new address[](VALIDATOR_COUNT);
+    for (uint256 i = 1; i <= VALIDATOR_COUNT; i++) {
+      uint256 privateKey = uint256(keccak256(abi.encode("validator", i)));
+      address validator = vm.addr(privateKey);
+      privateKeys[validator] = privateKey;
+      validators[i - 1] = validator;
+      initialValidators[i - 1] = validator;
+    }
+
+    rollup =
+      new Rollup(new MockFeeJuicePortal(), bytes32(0), bytes32(0), address(this), initialValidators);
+
+    registry.upgrade(address(rollup));
+
+    registry.transferOwnership(address(apella));
+  }
+
+  function test_UpgradeIntoNewVersion() external {
+    payload = IPayload(address(new NewGerousiaPayload(registry)));
+    vm.warp(Timestamp.unwrap(rollup.getTimestampForSlot(Slot.wrap(1))));
+
+    for (uint256 i = 0; i < 10; i++) {
+      address proposer = rollup.getCurrentProposer();
+      vm.prank(proposer);
+      gerousia.vote(payload);
+      vm.warp(Timestamp.unwrap(rollup.getTimestampForSlot(rollup.getCurrentSlot() + Slot.wrap(1))));
+    }
+
+    gerousia.pushProposal(0);
+    proposal = apella.getProposal(0);
+    assertEq(address(proposal.payload), address(payload));
+
+    token.mint(EMPEROR, 10000 ether);
+
+    vm.startPrank(EMPEROR);
+    token.approve(address(apella), 10000 ether);
+    apella.deposit(EMPEROR, 10000 ether);
+    vm.stopPrank();
+
+    vm.warp(Timestamp.unwrap(proposal.pendingThrough()) + 1);
+    assertTrue(apella.getProposalState(0) == DataStructures.ProposalState.Active);
+
+    vm.prank(EMPEROR);
+    apella.vote(0, 10000 ether, true);
+
+    vm.warp(Timestamp.unwrap(proposal.activeThrough()) + 1);
+    assertTrue(apella.getProposalState(0) == DataStructures.ProposalState.Queued);
+
+    vm.warp(Timestamp.unwrap(proposal.queuedThrough()) + 1);
+    assertTrue(apella.getProposalState(0) == DataStructures.ProposalState.Executable);
+    assertEq(apella.gerousia(), address(gerousia));
+
+    apella.execute(0);
+
+    assertNotEq(apella.gerousia(), address(gerousia));
+    address newGerousia = address(NewGerousiaPayload(address(payload)).NEW_GEROUSIA());
+    assertEq(apella.gerousia(), newGerousia);
+
+    // Ensure that we cannot push a proposal after the upgrade.
+    vm.expectRevert(
+      abi.encodeWithSelector(
+        Errors.Apella__CallerNotGerousia.selector, address(gerousia), newGerousia
+      )
+    );
+    vm.prank(address(gerousia));
+    apella.propose(payload);
+  }
+}
diff --git a/l1-contracts/test/sparta/Sparta.t.sol b/l1-contracts/test/sparta/Sparta.t.sol
index b902092f66c..56e7d6df7ba 100644
--- a/l1-contracts/test/sparta/Sparta.t.sol
+++ b/l1-contracts/test/sparta/Sparta.t.sol
@@ -17,8 +17,6 @@ import {NaiveMerkle} from "../merkle/Naive.sol";
 import {MerkleTestUtil} from "../merkle/TestUtil.sol";
 import {TestERC20} from "@aztec/mock/TestERC20.sol";
 import {TxsDecoderHelper} from "../decoders/helpers/TxsDecoderHelper.sol";
-import {IFeeJuicePortal} from "@aztec/core/interfaces/IFeeJuicePortal.sol";
-import {IProofCommitmentEscrow} from "@aztec/core/interfaces/IProofCommitmentEscrow.sol";
 import {MessageHashUtils} from "@oz/utils/cryptography/MessageHashUtils.sol";
 import {MockFeeJuicePortal} from "@aztec/mock/MockFeeJuicePortal.sol";