diff --git a/android/app/build.gradle.kts b/android/app/build.gradle.kts
index 9eddf4c..0abb597 100644
--- a/android/app/build.gradle.kts
+++ b/android/app/build.gradle.kts
@@ -13,8 +13,8 @@ android {
         applicationId = "org.maturita.maturita"
         minSdk = 26
         targetSdk = 35
-        versionCode = 4
-        versionName = "android-4"
+        versionCode = 5
+        versionName = "android-5"
         buildConfigField("String", "COMMIT", "\"$commit\"")
         buildConfigField("String", "UPDATE_REPO", "\"pepaskopec-blip/maturita.c\"")
         buildConfigField("String", "UPDATE_BRANCH", "\"builds\"")
diff --git a/android/app/src/main/java/org/maturita/maturita/update/Updater.kt b/android/app/src/main/java/org/maturita/maturita/update/Updater.kt
index dad9196..74292ef 100644
--- a/android/app/src/main/java/org/maturita/maturita/update/Updater.kt
+++ b/android/app/src/main/java/org/maturita/maturita/update/Updater.kt
@@ -2,8 +2,11 @@ package org.maturita.maturita.update
 
 import android.app.Application
 import android.content.Intent
+import android.net.Uri
+import android.os.Build
 import android.os.Handler
 import android.os.Looper
+import android.provider.Settings
 import androidx.core.content.FileProvider
 import org.maturita.maturita.BuildConfig
 import java.io.File
@@ -22,6 +25,8 @@ data class UpdateState(
 class Updater(private val app: Application) {
     private val io = Executors.newSingleThreadExecutor()
     private val main = Handler(Looper.getMainLooper())
+    private val repo = BuildConfig.UPDATE_REPO
+    private val branch = BuildConfig.UPDATE_BRANCH
 
     private fun emit(cb: (UpdateState) -> Unit, state: UpdateState) {
         main.post { cb(state) }
@@ -35,18 +40,17 @@ class Updater(private val app: Application) {
         emit(cb, UpdateState(status = "checking", messageKey = "update_checking", messageArg = null))
         io.execute {
             try {
-                val atom = get("https://github.com/${BuildConfig.UPDATE_REPO}/commits/${BuildConfig.UPDATE_BRANCH}.atom")
-                val sha = Regex("""<id>.*?/commit/([0-9a-f]{7,40})</id>""", RegexOption.IGNORE_CASE)
-                    .find(atom)?.groupValues?.get(1)
-                    ?: throw IllegalStateException("sha")
-                val version = get(
-                    "https://raw.githubusercontent.com/${BuildConfig.UPDATE_REPO}/$sha/VERSION",
-                ).trim()
+                val atom = get("https://github.com/$repo/commits/$branch.atom")
+                val remote = atomMainSha(atom)
+                    ?: run {
+                        val tip = atomTip(atom) ?: error("sha")
+                        get("https://raw.githubusercontent.com/$repo/$tip/VERSION").trim()
+                    }
                 val local = BuildConfig.COMMIT
-                if (version.startsWith(local) || local.startsWith(version)) {
-                    emit(cb, UpdateState("ok", version, "update_uptodate", version.take(7)))
+                if (sameCommit(remote, local)) {
+                    emit(cb, UpdateState("ok", remote, "update_uptodate", remote.take(7)))
                 } else {
-                    emit(cb, UpdateState("available", version, "update_available", version.take(7), true))
+                    emit(cb, UpdateState("available", remote, "update_available", remote.take(7), true))
                 }
             } catch (_: Exception) {
                 emit(cb, UpdateState("error", messageKey = "update_err_network", messageArg = null))
@@ -58,11 +62,20 @@ class Updater(private val app: Application) {
         emit(cb, UpdateState(status = "downloading", messageKey = "update_downloading", messageArg = null))
         io.execute {
             try {
-                val atom = get("https://github.com/${BuildConfig.UPDATE_REPO}/commits/${BuildConfig.UPDATE_BRANCH}.atom")
-                val sha = Regex("""<id>.*?/commit/([0-9a-f]{7,40})</id>""", RegexOption.IGNORE_CASE)
-                    .find(atom)?.groupValues?.get(1)
-                    ?: throw IllegalStateException("sha")
-                val url = "https://raw.githubusercontent.com/${BuildConfig.UPDATE_REPO}/$sha/maturita-android.apk"
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O &&
+                    !app.packageManager.canRequestPackageInstalls()
+                ) {
+                    val settings = Intent(Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES).apply {
+                        data = Uri.parse("package:${app.packageName}")
+                        flags = Intent.FLAG_ACTIVITY_NEW_TASK
+                    }
+                    main.post { app.startActivity(settings) }
+                    emit(cb, UpdateState("error", messageKey = "update_err_download", messageArg = null))
+                    return@execute
+                }
+                val atom = get("https://github.com/$repo/commits/$branch.atom")
+                val tip = atomTip(atom) ?: error("sha")
+                val url = "https://raw.githubusercontent.com/$repo/$tip/maturita-android.apk"
                 val dir = File(app.cacheDir, "updates").apply { mkdirs() }
                 val apk = File(dir, "maturita.apk")
                 download(url, apk)
@@ -77,13 +90,25 @@ class Updater(private val app: Application) {
                     flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_GRANT_READ_URI_PERMISSION
                 }
                 main.post { app.startActivity(intent) }
-                emit(cb, UpdateState("staged", sha, "update_staged", sha.take(7)))
+                emit(cb, UpdateState("staged", tip, "update_staged", tip.take(7)))
             } catch (_: Exception) {
                 emit(cb, UpdateState("error", messageKey = "update_err_download", messageArg = null))
             }
         }
     }
 
+    private fun atomTip(atom: String): String? =
+        Regex("""Commit/([0-9a-f]{40})""", RegexOption.IGNORE_CASE).find(atom)?.groupValues?.get(1)
+            ?: Regex("""/commit/([0-9a-f]{7,40})""", RegexOption.IGNORE_CASE).find(atom)?.groupValues?.get(1)
+
+    private fun atomMainSha(atom: String): String? =
+        Regex("""Build from ([0-9a-f]{7,40})""", RegexOption.IGNORE_CASE).find(atom)?.groupValues?.get(1)
+
+    private fun sameCommit(a: String, b: String): Boolean {
+        val n = minOf(a.length, b.length)
+        return n >= 7 && a.take(n).equals(b.take(n), ignoreCase = true)
+    }
+
     private fun isApk(file: File): Boolean {
         if (file.length() < 1_000_000L) return false
         file.inputStream().use { input ->
@@ -93,12 +118,18 @@ class Updater(private val app: Application) {
         }
     }
 
-    private fun get(url: String): String {
-        val c = (URL(url).openConnection() as HttpURLConnection).apply {
+    private fun open(url: String, readMs: Int): HttpURLConnection {
+        return (URL(url).openConnection() as HttpURLConnection).apply {
             connectTimeout = 15000
-            readTimeout = 15000
+            readTimeout = readMs
             instanceFollowRedirects = true
+            setRequestProperty("User-Agent", "maturita.c-android")
+            setRequestProperty("Accept", "*/*")
         }
+    }
+
+    private fun get(url: String): String {
+        val c = open(url, 15000)
         return try {
             if (c.responseCode !in 200..299) error("http ${c.responseCode}")
             c.inputStream.bufferedReader().use { it.readText() }
@@ -108,11 +139,7 @@ class Updater(private val app: Application) {
     }
 
     private fun download(url: String, dest: File) {
-        val c = (URL(url).openConnection() as HttpURLConnection).apply {
-            connectTimeout = 20000
-            readTimeout = 60000
-            instanceFollowRedirects = true
-        }
+        val c = open(url, 60000)
         try {
             if (c.responseCode !in 200..299) error("http ${c.responseCode}")
             c.inputStream.use { input -> dest.outputStream().use { input.copyTo(it) } }