Deprecated Node 16, added Node 21. (#6051)

* Deprecated Node 16, added Node 21.

* Added Node 21 to frontend.

.github/workflows/backend-tests.yml

@@ -18,7 +18,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node: [16, 18, 20]
+        node: [18, 20, 21]
     steps:
       -
         name: Checkout repository
@@ -55,7 +55,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node: [16, 18, 20]
+        node: [18, 20, 21]
     steps:
       -
         name: Checkout repository

.github/workflows/frontend-admin-tests.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node: [19, 20]
+        node: [19, 20, 21]
 
     steps:
       -

.github/workflows/upgrade-from-latest-release.yml

@@ -18,7 +18,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node: [16, 18, 20]
+        node: [18, 20, 21]
     steps:
       -
         name: Check out latest release

src/package.json

@@ -93,7 +93,7 @@
     "typescript": "^5.3.2"
   },
   "engines": {
-    "node": ">=16.20.1",
+    "node": ">=18.18.2",
     "npm": ">=6.14.0"
   },
   "repository": {