diff --git a/demo/package-lock.json b/demo/package-lock.json
index 4b63f55351..a0d47481e7 100644
--- a/demo/package-lock.json
+++ b/demo/package-lock.json
@@ -6728,9 +6728,9 @@
       "integrity": "sha512-pISE66AbVkp4fDQ7VHBwRNXzAAKJjw4Vw7nWI/+Q3vuly7SNfgYXvm6i5IgFylHGK5sP/xHAbB7N49OS4gWNyQ=="
     },
     "preact-render-to-string": {
-      "version": "5.0.2",
-      "resolved": "https://registry.npmjs.org/preact-render-to-string/-/preact-render-to-string-5.0.2.tgz",
-      "integrity": "sha512-2RFtynyc8O+JA1Rlt7cPAnBKpQCr2M3R9BUXcHFsG0o6+BUTf3HRtbiV/XdEBaFapOEk+OlCnfvDw1L00G/Lmw==",
+      "version": "5.1.21",
+      "resolved": "https://registry.npmjs.org/preact-render-to-string/-/preact-render-to-string-5.1.21.tgz",
+      "integrity": "sha512-wbMtNU4JpfvbE04iCe7BZ1yLYN8i6NRrq+NhR0fUINjPXGu3ZIc4GM5ScOiwdIP1sPXv9SVETuud/tmQGMvdNQ==",
       "requires": {
         "pretty-format": "^3.8.0"
       }
diff --git a/demo/package.json b/demo/package.json
index 21cfb36b15..2ec364ff61 100644
--- a/demo/package.json
+++ b/demo/package.json
@@ -33,7 +33,7 @@
     "mobx": "^5.15.4",
     "mobx-react": "^6.2.2",
     "mobx-state-tree": "^3.16.0",
-    "preact-render-to-string": "^5.0.2",
+    "preact-render-to-string": "^5.1.21",
     "preact-router": "^3.0.0",
     "react-redux": "^7.1.0",
     "react-router": "^5.0.1",