diff --git a/package.json b/package.json
index 5a5da7f..ce2f694 100644
--- a/package.json
+++ b/package.json
@@ -23,7 +23,7 @@
     "@nomiclabs/hardhat-truffle5": "^2.0.2",
     "@nomiclabs/hardhat-waffle": "^2.0.1",
     "@nomiclabs/hardhat-web3": "^2.0.0",
-    "@openzeppelin/contracts": "3.4.0",
+    "@openzeppelin/contracts": "4.7.3",
     "@truffle/hdwallet-provider": "^1.5.1",
     "chai": "^4.2.0",
     "chai-arrays": "^2.2.0",
diff --git a/yarn.lock b/yarn.lock
index 0eee297..9ccf46c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2151,10 +2151,10 @@
     widest-line "^3.1.0"
     wrap-ansi "^4.0.0"
 
-"@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@4.7.3":
+  version "4.7.3"
+  resolved "https://registry.yarnpkg.com/@openzeppelin/contracts/-/contracts-4.7.3.tgz#939534757a81f8d69cc854c7692805684ff3111e"
+  integrity sha512-dGRS0agJzu8ybo44pCIf3xBaPQN/65AIXNgK8+4gzKd5kbvlqyxryUYVLJv7fK98Seyd2hDZzVEHSWAh0Bt1Yw==
 
 "@protobufjs/aspromise@^1.1.1", "@protobufjs/aspromise@^1.1.2":
   version "1.1.2"