diff --git a/build.ps1 b/build.ps1
index 738d357..001b537 100644
--- a/build.ps1
+++ b/build.ps1
@@ -31,17 +31,33 @@ try {
 
     $out = Join-Path $OutDir "roadamp.exe"
 
-    Write-Host "Building roadamp $Version → $out" -ForegroundColor Cyan
+    Write-Host "Building roadamp $Version -> $out" -ForegroundColor Cyan
 
-    $env:GOOS   = "windows"
-    $env:GOARCH = "amd64"
-    $env:CGO_ENABLED = "0"
+    # ── Patch sw.js with build version ────────────────────────────────────────
+    # The service worker embeds a cache-bust token so installed PWA clients
+    # pick up new assets after each release. We replace __BUILDVER__ in the
+    # source file, run go build (which embeds it), then restore via git.
+    $swPath = Join-Path $PSScriptRoot 'web\static\sw.js'
+    $swOriginal = Get-Content $swPath -Raw
+    try {
+        $swPatched = $swOriginal -replace '__BUILDVER__', $Version
+        [System.IO.File]::WriteAllText($swPath, $swPatched, [System.Text.Encoding]::UTF8)
 
-    go build `
-        -trimpath `
-        -ldflags "-s -w -X main.Version=$Version" `
-        -o $out `
-        ./cmd/roadamp
+        # ── Compile ───────────────────────────────────────────────────────────
+        $env:GOOS        = "windows"
+        $env:GOARCH      = "amd64"
+        $env:CGO_ENABLED = "0"
+
+        go build `
+            -trimpath `
+            -ldflags "-s -w -X main.Version=$Version" `
+            -o $out `
+            ./cmd/roadamp
+    }
+    finally {
+        # Always restore sw.js so the template token is preserved in the repo.
+        [System.IO.File]::WriteAllText($swPath, $swOriginal, [System.Text.Encoding]::UTF8)
+    }
 
     $size = [math]::Round((Get-Item $out).Length / 1MB, 2)
     Write-Host "Done  $out  (${size} MB)" -ForegroundColor Green
diff --git a/web/static/sw.js b/web/static/sw.js
index 24e2d0d..5bf6aa8 100644
--- a/web/static/sw.js
+++ b/web/static/sw.js
@@ -1,6 +1,9 @@
-'use strict';
+'use strict';
 
-const CACHE = 'roadamp-v1';
+// Cache name is injected by build.ps1 (token replaced with git version).
+// When the binary is built without the script, __BUILDVER__ stays literal
+// and the SW still works — it just won't auto-bust on updates.
+const CACHE = 'roadamp-__BUILDVER__';
 const SHELL = ['/', '/app.js', '/style.css', '/manifest.json', '/icon.svg'];
 
 self.addEventListener('install', e => {