diff --git a/.npmrc b/.npmrc
index 1dab4ed4c3020..aafab1669bf72 100644
--- a/.npmrc
+++ b/.npmrc
@@ -1 +1,2 @@
 save-exact = true
+engine-strict = true
diff --git a/package.json b/package.json
index 825a5714bfe1e..6429aea0b1c93 100644
--- a/package.json
+++ b/package.json
@@ -8,7 +8,7 @@
 	},
 	"engines": {
 		"node": ">=14.15.0",
-		"npm": ">=6.14.8"
+		"npm": ">=6.14.8 <7"
 	},
 	"author": "The WordPress Contributors",
 	"license": "GPL-2.0-or-later",