diff --git a/.gitea/workflows/release.yaml b/.gitea/workflows/release.yaml
index 855975b..4ecb6a5 100644
--- a/.gitea/workflows/release.yaml
+++ b/.gitea/workflows/release.yaml
@@ -90,6 +90,18 @@ jobs:
           mkdir -p build
           cp app/build/outputs/apk/release/app-release.apk build/FitnessDroid.apk
           (cd build && sha256sum FitnessDroid.apk > checksums.txt && ls -la)
+          # version.json för appens inbyggda uppdateringskoll
+          VN=$("$HOME/ci-tools/build-tools/aapt2" dump badging build/FitnessDroid.apk \
+            | sed -n "s/.*versionName='\([^']*\)'.*/\1/p" | head -1)
+          SHA=$(cut -d' ' -f1 build/checksums.txt)
+          jq -n \
+            --argjson code "${{ github.run_number }}" \
+            --arg name "$VN" \
+            --arg sha "$SHA" \
+            --arg url "https://gitea.brasse-pc.eu/${{ github.repository }}/releases/download/latest/FitnessDroid.apk" \
+            '{versionCode:$code, versionName:$name, sha256:$sha, apkUrl:$url}' \
+            > build/version.json
+          cat build/version.json
 
       - name: Skapa/uppdatera latest-release + ladda upp APK
         env:
@@ -124,7 +136,7 @@ jobs:
               -d "$(jq -n --arg body "$BODY" '{body:$body}')" -o /dev/null
           fi
           echo "release id: $rid"
-          for f in FitnessDroid.apk checksums.txt; do
+          for f in FitnessDroid.apk checksums.txt version.json; do
             aid=$(curl -s "$API/repos/$REPO/releases/$rid/assets" \
               -H "Authorization: token $TOKEN" | jq -r ".[] | select(.name==\"$f\") | .id")
             if [ -n "$aid" ] && [ "$aid" != "null" ]; then
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 3197298..d674e5d 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -3,6 +3,7 @@
 
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.VIBRATE" />
+    <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />
 
     <application
         android:name=".FitnessDroidApplication"
@@ -11,6 +12,16 @@
         android:supportsRtl="true"
         android:theme="@style/Theme.FitnessDroid">
 
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.fileprovider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/file_paths" />
+        </provider>
+
         <activity
             android:name=".MainActivity"
             android:exported="true"
diff --git a/app/src/main/java/eu/brassepc/fitnessdroid/FitnessDroidApplication.kt b/app/src/main/java/eu/brassepc/fitnessdroid/FitnessDroidApplication.kt
index 9e8d4de..b0c230c 100644
--- a/app/src/main/java/eu/brassepc/fitnessdroid/FitnessDroidApplication.kt
+++ b/app/src/main/java/eu/brassepc/fitnessdroid/FitnessDroidApplication.kt
@@ -11,6 +11,7 @@ import eu.brassepc.fitnessdroid.data.RestTimerController
 import eu.brassepc.fitnessdroid.data.SettingsStore
 import eu.brassepc.fitnessdroid.data.SyncEngine
 import eu.brassepc.fitnessdroid.data.TokenStore
+import eu.brassepc.fitnessdroid.data.UpdateChecker
 import eu.brassepc.fitnessdroid.data.local.AppDatabase
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
@@ -29,6 +30,7 @@ class AppContainer(context: Context) {
     val syncEngine = SyncEngine(database, graphQlClient, authRepository, appScope)
     val gymRepository = GymRepository(database, graphQlClient, authRepository, syncEngine, tokenStore, appScope)
     val restTimer = RestTimerController(context, settingsStore, appScope)
+    val updateChecker = UpdateChecker(context)
 }
 
 class FitnessDroidApplication : Application() {
diff --git a/app/src/main/java/eu/brassepc/fitnessdroid/data/UpdateChecker.kt b/app/src/main/java/eu/brassepc/fitnessdroid/data/UpdateChecker.kt
new file mode 100644
index 0000000..c1a5844
--- /dev/null
+++ b/app/src/main/java/eu/brassepc/fitnessdroid/data/UpdateChecker.kt
@@ -0,0 +1,109 @@
+package eu.brassepc.fitnessdroid.data
+
+import android.content.Context
+import android.content.Intent
+import androidx.core.content.FileProvider
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.intOrNull
+import kotlinx.serialization.json.jsonObject
+import kotlinx.serialization.json.jsonPrimitive
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import java.io.File
+import java.security.MessageDigest
+import java.util.concurrent.TimeUnit
+
+data class UpdateInfo(
+    val versionCode: Long,
+    val versionName: String,
+    val apkUrl: String,
+    val sha256: String?,
+)
+
+/**
+ * Uppdateringskoll mot släppsidans version.json (skrivs av CI:t).
+ * Nedladdning till appens cache + verifiering, sedan Androids
+ * installationsdialog — samma signeringsnyckel gör att den uppdaterar
+ * rakt över befintlig installation.
+ */
+class UpdateChecker(private val context: Context) {
+
+    private val http = OkHttpClient.Builder()
+        .connectTimeout(10, TimeUnit.SECONDS)
+        .readTimeout(120, TimeUnit.SECONDS)
+        .build()
+
+    private fun installedVersionCode(): Long =
+        context.packageManager.getPackageInfo(context.packageName, 0).longVersionCode
+
+    /** null = uppdaterad, nätfel eller trasig manifest — stör aldrig användaren. */
+    suspend fun check(): UpdateInfo? = withContext(Dispatchers.IO) {
+        runCatching {
+            val request = Request.Builder().url(VERSION_URL).build()
+            http.newCall(request).execute().use { response ->
+                if (!response.isSuccessful) return@withContext null
+                val o = Json.parseToJsonElement(response.body!!.string()).jsonObject
+                val info = UpdateInfo(
+                    versionCode = (o["versionCode"]?.jsonPrimitive?.intOrNull ?: 0).toLong(),
+                    versionName = o["versionName"]?.jsonPrimitive?.content ?: "?",
+                    apkUrl = o["apkUrl"]?.jsonPrimitive?.content ?: return@withContext null,
+                    sha256 = o["sha256"]?.jsonPrimitive?.content,
+                )
+                if (info.versionCode > installedVersionCode()) info else null
+            }
+        }.getOrNull()
+    }
+
+    /** Laddar ner APK:n till cachen, verifierar sha256, returnerar filen. */
+    suspend fun download(info: UpdateInfo, onProgress: (Float) -> Unit): File =
+        withContext(Dispatchers.IO) {
+            val dir = File(context.cacheDir, "updates").apply { mkdirs() }
+            val file = File(dir, "FitnessDroid-${info.versionCode}.apk")
+            val request = Request.Builder().url(info.apkUrl).build()
+            http.newCall(request).execute().use { response ->
+                if (!response.isSuccessful) error("HTTP ${response.code}")
+                val body = response.body!!
+                val total = body.contentLength().takeIf { it > 0 }
+                val digest = MessageDigest.getInstance("SHA-256")
+                body.byteStream().use { input ->
+                    file.outputStream().use { output ->
+                        val buffer = ByteArray(64 * 1024)
+                        var read: Int
+                        var done = 0L
+                        while (input.read(buffer).also { read = it } != -1) {
+                            output.write(buffer, 0, read)
+                            digest.update(buffer, 0, read)
+                            done += read
+                            total?.let { onProgress(done.toFloat() / it) }
+                        }
+                    }
+                }
+                val actual = digest.digest().joinToString("") { "%02x".format(it) }
+                if (info.sha256 != null && !actual.equals(info.sha256, ignoreCase = true)) {
+                    file.delete()
+                    error("sha256 stämmer inte — avbryter")
+                }
+            }
+            file
+        }
+
+    /** Öppnar Androids installationsdialog för den nedladdade APK:n. */
+    fun install(file: File) {
+        val uri = FileProvider.getUriForFile(
+            context, "${context.packageName}.fileprovider", file,
+        )
+        context.startActivity(
+            Intent(Intent.ACTION_VIEW).apply {
+                setDataAndType(uri, "application/vnd.android.package-archive")
+                addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_ACTIVITY_NEW_TASK)
+            }
+        )
+    }
+
+    companion object {
+        private const val VERSION_URL =
+            "https://gitea.brasse-pc.eu/brasse/FitnessDroid/releases/download/latest/version.json"
+    }
+}
diff --git a/app/src/main/java/eu/brassepc/fitnessdroid/ui/home/HomeScreen.kt b/app/src/main/java/eu/brassepc/fitnessdroid/ui/home/HomeScreen.kt
index 97ea4f6..23276d7 100644
--- a/app/src/main/java/eu/brassepc/fitnessdroid/ui/home/HomeScreen.kt
+++ b/app/src/main/java/eu/brassepc/fitnessdroid/ui/home/HomeScreen.kt
@@ -18,6 +18,7 @@ import androidx.compose.material.icons.filled.CloudOff
 import androidx.compose.material.icons.filled.CloudUpload
 import androidx.compose.material.icons.filled.PlayArrow
 import androidx.compose.material.icons.filled.Star
+import androidx.compose.material.icons.filled.SystemUpdate
 import androidx.compose.material3.AssistChip
 import androidx.compose.material3.Button
 import androidx.compose.material3.Card
@@ -40,6 +41,7 @@ fun HomeScreen(
     viewModel: HomeViewModel = viewModel(factory = HomeViewModel.Factory),
 ) {
     val uiState by viewModel.uiState.collectAsStateWithLifecycle()
+    val updateState by viewModel.updateState.collectAsStateWithLifecycle()
 
     Column(
         modifier = Modifier
@@ -60,6 +62,55 @@ fun HomeScreen(
             SyncChip(status = uiState.syncStatus, pending = uiState.pendingCount)
         }
 
+        updateState?.let { update ->
+            Card(modifier = Modifier.fillMaxWidth()) {
+                Row(
+                    modifier = Modifier.padding(14.dp),
+                    verticalAlignment = Alignment.CenterVertically,
+                ) {
+                    Icon(
+                        Icons.Default.SystemUpdate,
+                        contentDescription = null,
+                        tint = MaterialTheme.colorScheme.primary,
+                    )
+                    Column(modifier = Modifier.weight(1f).padding(start = 10.dp)) {
+                        when (update) {
+                            is UpdateState.Available -> {
+                                Text(
+                                    "Ny version: ${update.info.versionName}",
+                                    style = MaterialTheme.typography.titleSmall,
+                                )
+                                Text(
+                                    "Laddas ner från släppsidan och installeras ovanpå",
+                                    style = MaterialTheme.typography.bodySmall,
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                                )
+                            }
+                            is UpdateState.Downloading -> {
+                                Text("Laddar ner …", style = MaterialTheme.typography.titleSmall)
+                                androidx.compose.material3.LinearProgressIndicator(
+                                    progress = { update.progress },
+                                    modifier = Modifier.fillMaxWidth().padding(top = 6.dp),
+                                )
+                            }
+                            is UpdateState.Failed -> {
+                                Text(
+                                    update.message,
+                                    style = MaterialTheme.typography.titleSmall,
+                                    color = MaterialTheme.colorScheme.error,
+                                )
+                            }
+                        }
+                    }
+                    if (update !is UpdateState.Downloading) {
+                        Button(onClick = viewModel::startUpdate) {
+                            Text(if (update is UpdateState.Failed) "Igen" else "Uppdatera")
+                        }
+                    }
+                }
+            }
+        }
+
         if (uiState.hasActiveSession) {
             Card(
                 modifier = Modifier
diff --git a/app/src/main/java/eu/brassepc/fitnessdroid/ui/home/HomeViewModel.kt b/app/src/main/java/eu/brassepc/fitnessdroid/ui/home/HomeViewModel.kt
index fdc0ebf..4808ad7 100644
--- a/app/src/main/java/eu/brassepc/fitnessdroid/ui/home/HomeViewModel.kt
+++ b/app/src/main/java/eu/brassepc/fitnessdroid/ui/home/HomeViewModel.kt
@@ -24,11 +24,43 @@ data class HomeUiState(
     val pendingCount: Int = 0,
 )
 
+sealed interface UpdateState {
+    data class Available(val info: eu.brassepc.fitnessdroid.data.UpdateInfo) : UpdateState
+    data class Downloading(val progress: Float) : UpdateState
+    data class Failed(val message: String) : UpdateState
+}
+
 class HomeViewModel(
     private val repo: GymRepository,
     auth: AuthRepository,
+    private val updateChecker: eu.brassepc.fitnessdroid.data.UpdateChecker,
 ) : ViewModel() {
 
+    val updateState = kotlinx.coroutines.flow.MutableStateFlow<UpdateState?>(null)
+
+    init {
+        viewModelScope.launch {
+            updateChecker.check()?.let { updateState.value = UpdateState.Available(it) }
+        }
+    }
+
+    fun startUpdate() {
+        val info = (updateState.value as? UpdateState.Available)?.info ?: return
+        viewModelScope.launch {
+            try {
+                updateState.value = UpdateState.Downloading(0f)
+                val file = updateChecker.download(info) { p ->
+                    updateState.value = UpdateState.Downloading(p)
+                }
+                updateChecker.install(file)
+                // Tillbaka till "tillgänglig" om installationen avbryts.
+                updateState.value = UpdateState.Available(info)
+            } catch (e: Exception) {
+                updateState.value = UpdateState.Failed("Nedladdningen misslyckades — försök igen")
+            }
+        }
+    }
+
     val uiState = combine(
         repo.activeSession,
         repo.startCards,
@@ -63,7 +95,7 @@ class HomeViewModel(
         val Factory: ViewModelProvider.Factory = viewModelFactory {
             initializer {
                 val c = appContainer()
-                HomeViewModel(c.gymRepository, c.authRepository)
+                HomeViewModel(c.gymRepository, c.authRepository, c.updateChecker)
             }
         }
     }
diff --git a/app/src/main/res/xml/file_paths.xml b/app/src/main/res/xml/file_paths.xml
new file mode 100644
index 0000000..c9cc257
--- /dev/null
+++ b/app/src/main/res/xml/file_paths.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<paths>
+    <cache-path name="updates" path="updates/" />
+</paths>