diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index e71518f..6210966 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -15,6 +15,7 @@ jobs:
     strategy:
       matrix:
         node-version: [16.x, 18.x, 20.x]
+        react-version: [16, 17, 18, 19]
 
     steps:
       - uses: actions/checkout@v4
@@ -23,6 +24,20 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
 
-      - run: npm ci
+      # Add caching
+      - uses: actions/cache@v3
+        id: npm-cache
+        with:
+          path: node_modules
+          key: ${{ runner.os }}-node-${{ matrix.node-version }}-${{ hashFiles('**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-${{ matrix.node-version }}-
+
+      # Only run npm ci if cache missed
+      - if: steps.npm-cache.outputs.cache-hit != 'true'
+        run: npm ci
+
+      # Override React versions
+      - run: npm install --no-save react@^${{ matrix.react-version }} react-is@^${{ matrix.react-version }}
 
       - run: npm test
diff --git a/package.json b/package.json
index 8ae94ac..0b1a2c3 100644
--- a/package.json
+++ b/package.json
@@ -21,18 +21,10 @@
     "test": "tsx index.spec.tsx",
     "prepublishOnly": "npm run build"
   },
-  "keywords": [
-    "react",
-    "fragment",
-    "flatten",
-    "children",
-    "utility"
-  ],
+  "keywords": ["react", "fragment", "flatten", "children", "utility"],
   "author": "Tom McKenzie <tom@chillidonut.com>",
   "license": "MIT",
-  "files": [
-    "dist/"
-  ],
+  "files": ["dist/"],
   "devDependencies": {
     "@testing-library/dom": "^10.4.0",
     "@testing-library/react": "^16.2.0",
@@ -51,7 +43,7 @@
     "typescript": "^5.0.4"
   },
   "peerDependencies": {
-    "react": "^18.0.0 || ^19.0.0",
-    "react-is": "^18.0.0 || ^19.0.0"
+    "react": ">=15.0.0",
+    "react-is": ">=16.0.0"
   }
 }