diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index c9d881e..dfd8508 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -11,7 +11,7 @@ jobs:
   # Matrix test for all supported platforms and architectures
   
   integration-tests:
-    name: Test ${{ matrix.os }} (${{ matrix.arch }})
+    name: ${{ matrix.os }} (${{ matrix.arch }}) tailscale-${{ matrix.version }}
     strategy:
       fail-fast: false
       matrix:
@@ -20,31 +20,54 @@ jobs:
           - os: ubuntu-latest
             runner-os: Linux
             arch: amd64
+            version: latest
+
+          # Try unstable too
+          - os: ubuntu-latest
+            runner-os: Linux
+            arch: amd64
+            version: unstable
+
+          # Try a pinned version
+          - os: ubuntu-latest
+            runner-os: Linux
+            arch: amd64
+            version: 1.82.0
           
           # Linux tests (ARM64)
           - os: ubuntu-24.04-arm
             runner-os: Linux
             arch: arm64
+            version: latest
           
           # Windows tests (AMD64)
           - os: windows-latest
             runner-os: Windows
             arch: amd64
+            version: latest
+
+          - os: windows-latest
+            runner-os: Windows
+            arch: amd64
+            version: unstable
           
           # Windows tests (ARM64)
           - os: windows-11-arm
             runner-os: Windows
             arch: arm64
+            version: latest
             
           # macOS intel
           - os: macos-13
             runner-os: macOS
             arch: amd64
+            version: latest
           
           # macOS ARM
           - os: macos-14
             runner-os: macOS
             arch: arm64
+            version: latest
     
     runs-on: ${{ matrix.os }}
     
@@ -72,7 +95,7 @@ jobs:
           oauth-client-id: ${{ secrets.TS_AUTH_KEYS_OAUTH_CLIENT_ID }}
           oauth-client-secret: ${{ secrets.TS_AUTH_KEYS_OAUTH_CLIENT_SECRET }}
           tags: "tag:ci"
-          version: "1.82.0"
+          version: "${{ matrix.version }}"
           use-cache: false
           timeout: "5m"
           retry: 3
diff --git a/Makefile b/Makefile
index 07b1a87..9dc7685 100644
--- a/Makefile
+++ b/Makefile
@@ -26,7 +26,7 @@ install:
 	npm install
 
 # Build the TypeScript code
-build: clean
+build: clean format
 	npm run build
 
 # Lint the TypeScript code
diff --git a/dist/index.js b/dist/index.js
index f5a0829..94ed941 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -41204,10 +41204,15 @@ async function run() {
         }
         // Get and validate inputs
         const config = await getInputs();
+        if (runnerOS === "macOS" &&
+            config.version === "unstable" &&
+            config.useCache) {
+            throw new Error("Caching of unstable releases is not supported on macOS runners");
+        }
         // Validate authentication
         validateAuth(config);
         // Resolve version
-        config.resolvedVersion = await resolveVersion(config.version);
+        config.resolvedVersion = await resolveVersion(config.version, runnerOS);
         core.info(`Resolved Tailscale version: ${config.resolvedVersion}`);
         // Set architecture
         config.arch = getTailscaleArch(runnerOS);
@@ -41268,13 +41273,17 @@ function validateAuth(config) {
         throw new Error("OAuth identity empty, please provide either an auth key or OAuth secret and tags.");
     }
 }
-async function resolveVersion(version) {
-    if (version === "latest") {
+async function resolveVersion(version, runnerOS) {
+    if (runnerOS === "macOS" && version === "unstable") {
+        return "main";
+    }
+    if (version === "latest" || version === "unstable") {
+        let path = version === "unstable" ? "unstable" : "stable";
         const { stdout } = await exec.getExecOutput("curl", [
             "-H",
             "user-agent:action-setup-tailscale",
             "-s",
-            "https://pkgs.tailscale.com/stable/?mode=json",
+            `https://pkgs.tailscale.com/${path}/?mode=json`,
         ]);
         const response = JSON.parse(stdout);
         return response.Version;
@@ -41656,8 +41665,7 @@ function sleep(ms) {
     return new Promise((resolve) => setTimeout(resolve, ms));
 }
 function generateCacheKey(config, runnerOS) {
-    // Don't cache if version is latest or if caching is disabled
-    if (config.resolvedVersion === "latest" || !config.useCache) {
+    if (!config.useCache) {
         return undefined;
     }
     return `action-setup-tailscale/${config.resolvedVersion}/${runnerOS}-${config.arch}`;
diff --git a/src/main.ts b/src/main.ts
index 10e9519..2996009 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -114,11 +114,21 @@ async function run(): Promise<void> {
     // Get and validate inputs
     const config = await getInputs();
 
+    if (
+      runnerOS === "macOS" &&
+      config.version === "unstable" &&
+      config.useCache
+    ) {
+      throw new Error(
+        "Caching of unstable releases is not supported on macOS runners"
+      );
+    }
+
     // Validate authentication
     validateAuth(config);
 
     // Resolve version
-    config.resolvedVersion = await resolveVersion(config.version);
+    config.resolvedVersion = await resolveVersion(config.version, runnerOS);
     core.info(`Resolved Tailscale version: ${config.resolvedVersion}`);
 
     // Set architecture
@@ -186,17 +196,26 @@ function validateAuth(config: TailscaleConfig): void {
   }
 }
 
-async function resolveVersion(version: string): Promise<string> {
-  if (version === "latest") {
+async function resolveVersion(
+  version: string,
+  runnerOS: string
+): Promise<string> {
+  if (runnerOS === "macOS" && version === "unstable") {
+    return "main";
+  }
+
+  if (version === "latest" || version === "unstable") {
+    let path = version === "unstable" ? "unstable" : "stable";
     const { stdout } = await exec.getExecOutput("curl", [
       "-H",
       "user-agent:action-setup-tailscale",
       "-s",
-      "https://pkgs.tailscale.com/stable/?mode=json",
+      `https://pkgs.tailscale.com/${path}/?mode=json`,
     ]);
     const response = JSON.parse(stdout);
     return response.Version;
   }
+
   return version;
 }
 
@@ -665,8 +684,7 @@ function generateCacheKey(
   config: TailscaleConfig,
   runnerOS: string
 ): string | undefined {
-  // Don't cache if version is latest or if caching is disabled
-  if (config.resolvedVersion === "latest" || !config.useCache) {
+  if (!config.useCache) {
     return undefined;
   }