diff --git a/contracts/package.json b/contracts/package.json
index 3e5c158..396ff55 100644
--- a/contracts/package.json
+++ b/contracts/package.json
@@ -13,7 +13,7 @@
     "deploy:xdai": "hardhat deploy --network xdai"
   },
   "dependencies": {
-    "@openzeppelin/contracts": "^3.4.0"
+    "@openzeppelin/contracts": "^4.7.2"
   },
   "devDependencies": {
     "@nomiclabs/hardhat-ethers": "^2.0.1",
diff --git a/yarn.lock b/yarn.lock
index d1d4017..873f89a 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1955,10 +1955,10 @@
     "@types/sinon-chai" "^3.2.3"
     "@types/web3" "1.0.19"
 
-"@openzeppelin/contracts@^3.4.0":
-  version "3.4.0"
-  resolved "https://registry.yarnpkg.com/@openzeppelin/contracts/-/contracts-3.4.0.tgz#9a1669ad5f9fdfb6e273bb5a4fed10cb4cc35eb0"
-  integrity sha512-qh+EiHWzfY/9CORr+eRUkeEUP1WiFUcq3974bLHwyYzLBUtK6HPaMkIUHi74S1rDTZ0sNz42DwPc5A4IJvN3rg==
+"@openzeppelin/contracts@^4.7.2":
+  version "4.7.2"
+  resolved "https://registry.yarnpkg.com/@openzeppelin/contracts/-/contracts-4.7.2.tgz#7587416fe2d35abf574193515b8971bfe9f64bc7"
+  integrity sha512-4n/JL9izql8303mPqPdubuna/DWEMbmOzWYUWyCPhjhiEr2w3nQrjE7vZz1fBF+wzzP6dZbIcsgqACk53c9FGA==
 
 "@resolver-engine/core@^0.3.3":
   version "0.3.3"