diff --git a/contracts/Contribution.sol b/contracts/Contribution.sol
index 8c64106..d275b39 100644
--- a/contracts/Contribution.sol
+++ b/contracts/Contribution.sol
@@ -42,8 +42,15 @@ contract Contribution is Initializable {
   mapping(uint32 => ContributionData) public contributions;
   uint32 public contributionsCount;
 
+  // Confirmation veto period
   uint32 public blocksToWait;
 
+  // The address that deployed the contract
+  address public deployer;
+
+  // Data migration flag
+  bool public migrationDone;
+
   event ContributionAdded(uint32 id, uint32 indexed contributorId, uint32 amount);
   event ContributionClaimed(uint32 id, uint32 indexed contributorId, uint32 amount);
   event ContributionVetoed(uint32 id, address vetoedByAccount);
@@ -53,10 +60,21 @@ contract Contribution is Initializable {
     _;
   }
 
+  modifier onlyDeployer {
+    require(msg.sender == deployer, "Deployer only");
+    _;
+  }
+
   function initialize(uint32 blocksToWait_) public initializer {
+    deployer = msg.sender;
+    migrationDone = false;
     blocksToWait = blocksToWait_;
   }
 
+  function finishMigration() public onlyDeployer {
+    migrationDone = true;
+  }
+
   function setTokenContract(address token) public {
     require(address(tokenContract) == address(0) || contributorContract.addressIsCore(msg.sender), "Core only");
     tokenContract = IToken(token);
diff --git a/contracts/Contributor.sol b/contracts/Contributor.sol
index a2255b4..20f9b9c 100644
--- a/contracts/Contributor.sol
+++ b/contracts/Contributor.sol
@@ -99,7 +99,7 @@ contract Contributor is Initializable {
   function isCoreTeam(uint32 id) view public returns (bool) {
     // TODO: for simplicity we simply define the first contributors as core
     // later this needs to be changed to something more dynamic
-    return id > 0 && id < 7;
+    return id > 0 && id < 6;
   }
 
   function exists(uint32 id) view public returns (bool) {
diff --git a/hardhat.config.js b/hardhat.config.js
index d5d5681..1190ee2 100644
--- a/hardhat.config.js
+++ b/hardhat.config.js
@@ -1,6 +1,7 @@
 require("@nomiclabs/hardhat-waffle");
 require("hardhat-deploy");
 require("hardhat-deploy-ethers");
+require("@nomicfoundation/hardhat-chai-matchers");
 require("@openzeppelin/hardhat-upgrades");
 const Kredits = require("./lib/kredits");
 
diff --git a/package-lock.json b/package-lock.json
index ca5efda..3b2b2a9 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1216,6 +1216,12 @@
       "dependencies": {
         "@types/sinon-chai": "^3.2.3",
         "@types/web3": "1.0.19"
+      },
+      "peerDependencies": {
+        "@nomiclabs/hardhat-ethers": "^2.0.0",
+        "ethereum-waffle": "^3.2.0",
+        "ethers": "^5.0.0",
+        "hardhat": "^2.0.0"
       }
     },
     "node_modules/@openzeppelin/contracts-upgradeable": {
@@ -1708,9 +1714,9 @@
       }
     },
     "node_modules/@types/sinon": {
-      "version": "10.0.11",
-      "resolved": "https://registry.npmjs.org/@types/sinon/-/sinon-10.0.11.tgz",
-      "integrity": "sha512-dmZsHlBsKUtBpHriNjlK0ndlvEh8dcb9uV9Afsbt89QIyydpC7NcR+nWlAhASfy3GHnxTl4FX/aKE7XZUt/B4g==",
+      "version": "10.0.13",
+      "resolved": "https://registry.npmjs.org/@types/sinon/-/sinon-10.0.13.tgz",
+      "integrity": "sha512-UVjDqJblVNQYvVNUsj0PuYYw0ELRmgt1Nt5Vk0pT5f16ROGfcKJY8o1HVuMOJOpD727RrGB9EGvoaTQE5tgxZQ==",
       "dev": true,
       "dependencies": {
         "@types/sinonjs__fake-timers": "*"
@@ -21394,9 +21400,9 @@
       }
     },
     "@types/sinon": {
-      "version": "10.0.11",
-      "resolved": "https://registry.npmjs.org/@types/sinon/-/sinon-10.0.11.tgz",
-      "integrity": "sha512-dmZsHlBsKUtBpHriNjlK0ndlvEh8dcb9uV9Afsbt89QIyydpC7NcR+nWlAhASfy3GHnxTl4FX/aKE7XZUt/B4g==",
+      "version": "10.0.13",
+      "resolved": "https://registry.npmjs.org/@types/sinon/-/sinon-10.0.13.tgz",
+      "integrity": "sha512-UVjDqJblVNQYvVNUsj0PuYYw0ELRmgt1Nt5Vk0pT5f16ROGfcKJY8o1HVuMOJOpD727RrGB9EGvoaTQE5tgxZQ==",
       "dev": true,
       "requires": {
         "@types/sinonjs__fake-timers": "*"
diff --git a/test/Contribution.js b/test/Contribution.js
index ef874ca..cb3fae2 100644
--- a/test/Contribution.js
+++ b/test/Contribution.js
@@ -1,18 +1,50 @@
 const { expect } = require("chai");
 const { ethers, upgrades } = require("hardhat");
-let hardhatContribution;
+let owner, addr1, addr2, addr3, addr4, addr5, addr6;
+let Contribution, Contributor;
 
-describe("Contribution contract", function () {
+describe("Contribution contract", async function () {
+  before(async function () {
+    [owner, addr1, addr2, addr3, addr4, addr5, addr6] = await ethers.getSigners();
+    let accounts = [owner, addr1, addr2, addr3, addr4, addr5, addr6];
+    const contributorFactory = await ethers.getContractFactory("Contributor");
+    Contributor = await upgrades.deployProxy(contributorFactory);
+    for (const account of accounts) {
+      await Contributor.addContributor(account.address, "0x99b8afd7b266e19990924a8be9099e81054b70c36b20937228a77a5cf75723b8", 18, 32);
+    }
+  });
 
   describe("Deployment", function () {
     before(async function () {
       // const [owner] = await ethers.getSigners();
-      const Contribution = await ethers.getContractFactory("Contribution");
-      hardhatContribution = await upgrades.deployProxy(Contribution, [40321]);
+      const contributionFactory = await ethers.getContractFactory("Contribution");
+      Contribution = await upgrades.deployProxy(contributionFactory, [40321]);
     });
 
     it("sets the veto confirmation period", async function () {
-      expect(await hardhatContribution.blocksToWait()).to.equal(40321);
+      expect(await Contribution.blocksToWait()).to.equal(40321);
+    });
+
+    it("sets the data migration flag", async function () {
+      expect(await Contribution.migrationDone()).to.equal(false);
+    });
+  });
+
+  describe("Data migration", function () {
+    before(async function () {
+      const contributionFactory = await ethers.getContractFactory("Contribution");
+      Contribution = await upgrades.deployProxy(contributionFactory, [40321]);
+      await Contribution.setContributorContract(Contributor.address).then(res => res.wait())
+    });
+
+    it("does not allow random accounts to mark the migration as finished", async function () {
+      await expect(Contribution.connect(addr1).finishMigration()).to.be.revertedWith("Deployer only");
+      expect(await Contribution.migrationDone()).to.equal(false);
+    });
+
+    it("allows the deployer to mark the migration as finished", async function () {
+      await Contribution.finishMigration();
+      expect(await Contribution.migrationDone()).to.equal(true);
     });
   });