diff --git a/apps/stage-tamagotchi/package.json b/apps/stage-tamagotchi/package.json
index 2789b25b5..0cd389680 100644
--- a/apps/stage-tamagotchi/package.json
+++ b/apps/stage-tamagotchi/package.json
@@ -112,6 +112,7 @@
     "reka-ui": "^2.9.2",
     "remark-parse": "^11.0.0",
     "remark-rehype": "^11.1.2",
+    "semver": "^7.7.4",
     "shiki": "^4.0.2",
     "splitpanes": "catalog:",
     "three": "^0.183.2",
@@ -161,6 +162,7 @@
     "@types/audioworklet": "catalog:",
     "@types/culori": "^4.0.1",
     "@types/nprogress": "^0.2.3",
+    "@types/semver": "^7.7.1",
     "@types/splitpanes": "catalog:",
     "@types/three": "^0.183.1",
     "@types/yauzl": "^2.10.3",
diff --git a/apps/stage-tamagotchi/src/main/services/electron/auto-updater.test.ts b/apps/stage-tamagotchi/src/main/services/electron/auto-updater.test.ts
index 6bf6f0f54..ae3365ddd 100644
--- a/apps/stage-tamagotchi/src/main/services/electron/auto-updater.test.ts
+++ b/apps/stage-tamagotchi/src/main/services/electron/auto-updater.test.ts
@@ -139,6 +139,15 @@ describe('setupAutoUpdater', () => {
     expect(service.state.diagnostics).not.toHaveProperty('uninstallExists')
   })
 
+  it('does not treat build metadata as prerelease', async () => {
+    appMock.getVersion.mockReturnValue('1.2.3+build-1')
+
+    const { setupAutoUpdater } = await import('./auto-updater')
+    setupAutoUpdater()
+
+    expect(updaterState.instance.allowPrerelease).toBe(false)
+  })
+
   it('uses silent relaunch install on Windows only', async () => {
     const originalPlatform = process.platform
     vi.stubEnv('TEST_PLATFORM', '')
diff --git a/apps/stage-tamagotchi/src/main/services/electron/auto-updater.ts b/apps/stage-tamagotchi/src/main/services/electron/auto-updater.ts
index 5d983e4c5..7cd3e6495 100644
--- a/apps/stage-tamagotchi/src/main/services/electron/auto-updater.ts
+++ b/apps/stage-tamagotchi/src/main/services/electron/auto-updater.ts
@@ -6,6 +6,7 @@ import type { UpdateInfo } from 'electron-updater'
 import process from 'node:process'
 
 import electronUpdater from 'electron-updater'
+import semver from 'semver'
 
 import { is } from '@electron-toolkit/utils'
 import { useLogg } from '@guiiai/logg'
@@ -14,6 +15,7 @@ import { errorMessageFrom, tryCatch } from '@moeru/std'
 import { committerDate } from '~build/git'
 import { app } from 'electron'
 import { Semaphore } from 'es-toolkit'
+import { isWindows } from 'std-env'
 
 import {
   autoUpdater as autoUpdaterEventa,
@@ -63,9 +65,13 @@ export interface AutoUpdater {
   subscribe: (callback: (state: AutoUpdaterState) => void) => () => void
 }
 
+function isPrereleaseVersion(version: string) {
+  return (semver.prerelease(version)?.length ?? 0) > 0
+}
+
 export function setupAutoUpdater(): AutoUpdater {
   const semaphore = new Semaphore(1)
-  const isPrereleaseBuild = app.getVersion().includes('-')
+  const isPrereleaseBuild = isPrereleaseVersion(app.getVersion())
   const log = useLogg('auto-updater').useGlobalConfig()
   const autoUpdater = fromImported()
   const feedUrlOverride = getUpdateServerOverride()
@@ -173,7 +179,7 @@ export function setupAutoUpdater(): AutoUpdater {
       await semaphore.acquire()
 
       try {
-        if (process.platform === 'win32')
+        if (isWindows)
           autoUpdater.quitAndInstall(true, true)
         else
           autoUpdater.quitAndInstall()
@@ -209,31 +215,21 @@ export function createAutoUpdaterService(params: { context: MainContext, window:
     tryCatch(() => context.emit(electronAutoUpdaterStateChanged, state))
   })
 
-  const cleanups: Array<() => void> = [unsubscribe]
-
-  cleanups.push(
+  const cleanups: Array<() => void> = [
+    unsubscribe,
     defineInvokeHandler(context, autoUpdaterEventa.getState, () => service.state),
-  )
-
-  cleanups.push(
     defineInvokeHandler(context, autoUpdaterEventa.checkForUpdates, async () => {
       await service.checkForUpdates().catch(error => log.withError(error).error('checkForUpdates() failed'))
       return service.state
     }),
-  )
-
-  cleanups.push(
     defineInvokeHandler(context, autoUpdaterEventa.downloadUpdate, async () => {
       await service.downloadUpdate()
       return service.state
     }),
-  )
-
-  cleanups.push(
     defineInvokeHandler(context, autoUpdaterEventa.quitAndInstall, async () => {
       await service.quitAndInstall()
     }),
-  )
+  ]
 
   const cleanup = () => {
     for (const fn of cleanups)
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 59f9f161b..7bd541f4d 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -1297,6 +1297,9 @@ importers:
       remark-rehype:
         specifier: ^11.1.2
         version: 11.1.2
+      semver:
+        specifier: ^7.7.4
+        version: 7.7.4
       shiki:
         specifier: ^4.0.2
         version: 4.0.2
@@ -1439,6 +1442,9 @@ importers:
       '@types/nprogress':
         specifier: ^0.2.3
         version: 0.2.3
+      '@types/semver':
+        specifier: ^7.7.1
+        version: 7.7.1
       '@types/splitpanes':
         specifier: 'catalog:'
         version: 2.2.6
@@ -9491,6 +9497,9 @@ packages:
   '@types/responselike@1.0.3':
     resolution: {integrity: sha512-H/+L+UkTV33uf49PH5pCAUBVPNj2nDBXTN+qS1dOwyyg24l3CcicicCA7ca+HMvJBZcFgl5r8e+RR6elsb4Lyw==}
 
+  '@types/semver@7.7.1':
+    resolution: {integrity: sha512-FmgJfu+MOcQ370SD0ev7EI8TlCAfKYU+B4m5T3yXc1CiRN94g/SZPtsCkk506aUDtlMnFZvasDwHHUcZUEaYuA==}
+
   '@types/slice-ansi@4.0.0':
     resolution: {integrity: sha512-+OpjSaq85gvlZAYINyzKpLeiFkSC4EsC6IIiT6v6TLSU5k5U83fHGj9Lel8oKEXM0HqgrMVCjXPDPVICtxF7EQ==}
 
@@ -23397,6 +23406,8 @@ snapshots:
     dependencies:
       '@types/node': 24.12.0
 
+  '@types/semver@7.7.1': {}
+
   '@types/slice-ansi@4.0.0': {}
 
   '@types/splitpanes@2.2.6':