diff --git a/app/build.gradle b/app/build.gradle
index 0370e738..bd3755c2 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -19,8 +19,8 @@ android {
         applicationId "xyz.quaver.pupil"
         minSdkVersion 16
         targetSdkVersion 29
-        versionCode 51
-        versionName "4.15"
+        versionCode 52
+        versionName "4.17"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         multiDexEnabled true
         vectorDrawables.useSupportLibrary = true
@@ -54,20 +54,19 @@ dependencies {
 
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
-    implementation "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.3'
     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.3'
-    implementation "org.jetbrains.kotlinx:kotlinx-serialization-runtime:0.14.0"
+    implementation "org.jetbrains.kotlinx:kotlinx-serialization-runtime:0.20.0"
     implementation 'androidx.appcompat:appcompat:1.1.0'
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
-    implementation 'androidx.preference:preference:1.1.0'
+    implementation 'androidx.preference:preference:1.1.1'
     implementation 'androidx.gridlayout:gridlayout:1.0.0'
     implementation "androidx.biometric:biometric:1.0.1"
     implementation 'androidx.multidex:multidex:2.0.1'
     implementation "com.daimajia.swipelayout:library:1.2.0@aar"
-    implementation 'com.google.android.material:material:1.2.0-alpha05'
-    implementation 'com.google.firebase:firebase-core:17.2.3'
-    implementation 'com.google.firebase:firebase-perf:19.0.5'
+    implementation 'com.google.android.material:material:1.3.0-alpha01'
+    implementation 'com.google.firebase:firebase-core:17.4.3'
+    implementation 'com.google.firebase:firebase-perf:19.0.7'
     implementation 'com.crashlytics.sdk.android:crashlytics:2.10.1'
     implementation 'com.github.arimorty:floatingsearchview:2.1.1'
     implementation 'com.github.clans:fab:1.6.4'
diff --git a/app/release/output.json b/app/release/output.json
index 5c7bd789..41aaa36f 100644
--- a/app/release/output.json
+++ b/app/release/output.json
@@ -1 +1 @@
-[{"outputType":{"type":"APK"},"apkData":{"type":"MAIN","splits":[],"versionCode":51,"versionName":"4.15","enabled":true,"outputFile":"app-release.apk","fullName":"release","baseName":"release","dirName":""},"path":"app-release.apk","properties":{}}]
\ No newline at end of file
+[{"outputType":{"type":"APK"},"apkData":{"type":"MAIN","splits":[],"versionCode":52,"versionName":"4.17","enabled":true,"outputFile":"app-release.apk","fullName":"release","baseName":"release","dirName":""},"path":"app-release.apk","properties":{}}]
\ No newline at end of file
diff --git a/app/src/main/java/xyz/quaver/pupil/Pupil.kt b/app/src/main/java/xyz/quaver/pupil/Pupil.kt
index 54543259..54b1b78c 100644
--- a/app/src/main/java/xyz/quaver/pupil/Pupil.kt
+++ b/app/src/main/java/xyz/quaver/pupil/Pupil.kt
@@ -59,6 +59,13 @@ class Pupil : MultiDexApplication() {
             preference.edit().remove("dl_location").apply()
         }
 
+        if (!preference.getBoolean("low_quality_reset", false)) {
+            preference.edit()
+                .putBoolean("low_quality", true)
+                .putBoolean("low_quality_reset", true)
+                .apply()
+        }
+
         histories = Histories(File(ContextCompat.getDataDir(this), "histories.json"))
         favorites = Histories(File(ContextCompat.getDataDir(this), "favorites.json"))
 
diff --git a/app/src/main/java/xyz/quaver/pupil/ui/MainActivity.kt b/app/src/main/java/xyz/quaver/pupil/ui/MainActivity.kt
index bf97d3a3..714d4fb2 100644
--- a/app/src/main/java/xyz/quaver/pupil/ui/MainActivity.kt
+++ b/app/src/main/java/xyz/quaver/pupil/ui/MainActivity.kt
@@ -52,7 +52,7 @@ import io.fabric.sdk.android.Fabric
 import kotlinx.android.synthetic.main.activity_main.*
 import kotlinx.android.synthetic.main.activity_main_content.*
 import kotlinx.coroutines.*
-import kotlinx.serialization.list
+import kotlinx.serialization.builtins.list
 import xyz.quaver.hitomi.GalleryBlock
 import xyz.quaver.hitomi.doSearch
 import xyz.quaver.hitomi.getGalleryIDsFromNozomi
@@ -367,6 +367,29 @@ class MainActivity : AppCompatActivity() {
             }
         }
 
+        with(main_fab_random) {
+            setImageResource(R.drawable.shuffle_variant)
+            setOnClickListener {
+                runBlocking {
+                    withTimeoutOrNull(100) {
+                        galleryIDs?.await()
+                    }
+                }.let {
+                    if (it?.isEmpty() == false) {
+                        val galleryID = it.random()
+
+                        val intent = Intent(this@MainActivity, ReaderActivity::class.java).apply {
+                            putExtra("galleryID", galleryID)
+                        }
+
+                        startActivity(intent)
+
+                        histories.add(galleryID)
+                    }
+                }
+            }
+        }
+
         with(main_fab_id) {
             setImageResource(R.drawable.numeric)
             setOnClickListener {
diff --git a/app/src/main/java/xyz/quaver/pupil/ui/SettingsActivity.kt b/app/src/main/java/xyz/quaver/pupil/ui/SettingsActivity.kt
index fecb401c..20621e38 100644
--- a/app/src/main/java/xyz/quaver/pupil/ui/SettingsActivity.kt
+++ b/app/src/main/java/xyz/quaver/pupil/ui/SettingsActivity.kt
@@ -30,8 +30,8 @@ import androidx.appcompat.app.AppCompatActivity
 import androidx.preference.PreferenceManager
 import com.google.android.material.snackbar.Snackbar
 import kotlinx.android.synthetic.main.settings_activity.*
-import kotlinx.serialization.list
-import kotlinx.serialization.serializer
+import kotlinx.serialization.builtins.list
+import kotlinx.serialization.builtins.serializer
 import net.rdrei.android.dirchooser.DirectoryChooserActivity
 import xyz.quaver.pupil.Pupil
 import xyz.quaver.pupil.R
diff --git a/app/src/main/java/xyz/quaver/pupil/util/download/Cache.kt b/app/src/main/java/xyz/quaver/pupil/util/download/Cache.kt
index 97edd6f1..617d3dd3 100644
--- a/app/src/main/java/xyz/quaver/pupil/util/download/Cache.kt
+++ b/app/src/main/java/xyz/quaver/pupil/util/download/Cache.kt
@@ -26,7 +26,6 @@ import android.util.SparseArray
 import androidx.preference.PreferenceManager
 import com.crashlytics.android.Crashlytics
 import kotlinx.coroutines.*
-import kotlinx.io.InputStream
 import xyz.quaver.Code
 import xyz.quaver.hitomi.GalleryBlock
 import xyz.quaver.hitomi.Reader
@@ -35,10 +34,11 @@ import xyz.quaver.pupil.util.getCachedGallery
 import xyz.quaver.pupil.util.getDownloadDirectory
 import xyz.quaver.pupil.util.isParentOf
 import xyz.quaver.pupil.util.json
+import java.io.BufferedInputStream
 import java.io.File
 import java.io.FileOutputStream
+import java.io.InputStream
 import java.net.URL
-import java.util.concurrent.Executors
 import java.util.concurrent.locks.Lock
 import java.util.concurrent.locks.ReentrantLock
 
@@ -245,7 +245,7 @@ class Cache(context: Context) : ContextWrapper(context) {
                 it.createNewFile()
         }
 
-        data.use {
+        BufferedInputStream(data).use {
             it.copyTo(FileOutputStream(cache))
         }
     }
diff --git a/app/src/main/java/xyz/quaver/pupil/util/download/DownloadWorker.kt b/app/src/main/java/xyz/quaver/pupil/util/download/DownloadWorker.kt
index eb05cc19..5c279c3b 100644
--- a/app/src/main/java/xyz/quaver/pupil/util/download/DownloadWorker.kt
+++ b/app/src/main/java/xyz/quaver/pupil/util/download/DownloadWorker.kt
@@ -46,11 +46,10 @@ import xyz.quaver.pupil.R
 import xyz.quaver.pupil.ui.ReaderActivity
 import java.io.File
 import java.io.IOException
-import java.util.concurrent.Executors
 import java.util.concurrent.LinkedBlockingQueue
 import java.util.concurrent.TimeUnit
 
-@UseExperimental(ExperimentalCoroutinesApi::class)
+@OptIn(ExperimentalCoroutinesApi::class)
 class DownloadWorker private constructor(context: Context) : ContextWrapper(context) {
 
     private val preferences : SharedPreferences = PreferenceManager.getDefaultSharedPreferences(this)
@@ -164,7 +163,10 @@ class DownloadWorker private constructor(context: Context) : ContextWrapper(cont
             .connectTimeout(0, TimeUnit.SECONDS)
             .addInterceptor(interceptor)
             .readTimeout(0, TimeUnit.SECONDS)
-            .dispatcher(Dispatcher(Executors.newFixedThreadPool(4)))
+            .dispatcher(Dispatcher().apply {
+                maxRequests = 4
+                maxRequestsPerHost = 4
+            })
             .proxy(proxy)
             .build()
 
@@ -222,7 +224,7 @@ class DownloadWorker private constructor(context: Context) : ContextWrapper(cont
                         imageUrlFromImage(
                             galleryID,
                             reader.galleryInfo.files[index],
-                            lowQuality
+                            !lowQuality
                         )
                     )
                     addHeader("Referer", getReferer(galleryID))
@@ -240,6 +242,8 @@ class DownloadWorker private constructor(context: Context) : ContextWrapper(cont
         }.build()
 
         client.newCall(request).enqueue(callback)
+
+        Log.i("PUPILD", "DOWNLOADING ($galleryID, $index) from ${request.url()}")
     }
 
     private fun download(galleryID: Int) = CoroutineScope(Dispatchers.IO).launch {
diff --git a/app/src/main/java/xyz/quaver/pupil/util/history.kt b/app/src/main/java/xyz/quaver/pupil/util/history.kt
index cb13c226..cc80275e 100644
--- a/app/src/main/java/xyz/quaver/pupil/util/history.kt
+++ b/app/src/main/java/xyz/quaver/pupil/util/history.kt
@@ -18,13 +18,14 @@
 
 package xyz.quaver.pupil.util
 
-import kotlinx.serialization.list
-import kotlinx.serialization.serializer
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.builtins.list
+import kotlinx.serialization.builtins.serializer
 import java.io.File
 
 class Histories(private val file: File) : ArrayList<Int>() {
 
-    val serializer = Int.serializer().list
+    val serializer: KSerializer<List<Int>> = Int.serializer().list
 
     init {
         if (!file.exists())
diff --git a/app/src/main/java/xyz/quaver/pupil/util/lock.kt b/app/src/main/java/xyz/quaver/pupil/util/lock.kt
index 4f48b784..44397450 100644
--- a/app/src/main/java/xyz/quaver/pupil/util/lock.kt
+++ b/app/src/main/java/xyz/quaver/pupil/util/lock.kt
@@ -22,9 +22,7 @@ import android.content.Context
 import android.content.ContextWrapper
 import androidx.core.content.ContextCompat
 import kotlinx.serialization.Serializable
-import kotlinx.serialization.json.Json
-import kotlinx.serialization.json.JsonConfiguration
-import kotlinx.serialization.list
+import kotlinx.serialization.builtins.list
 import java.io.File
 import java.security.MessageDigest
 
diff --git a/app/src/main/java/xyz/quaver/pupil/util/misc.kt b/app/src/main/java/xyz/quaver/pupil/util/misc.kt
index ddee2443..fafad368 100644
--- a/app/src/main/java/xyz/quaver/pupil/util/misc.kt
+++ b/app/src/main/java/xyz/quaver/pupil/util/misc.kt
@@ -22,7 +22,7 @@ import android.annotation.SuppressLint
 import java.util.*
 import kotlin.collections.ArrayList
 
-@UseExperimental(ExperimentalStdlibApi::class)
+@OptIn(ExperimentalStdlibApi::class)
 fun String.wordCapitalize() : String {
     val result = ArrayList<String>()
 
diff --git a/app/src/main/res/drawable/shuffle_variant.xml b/app/src/main/res/drawable/shuffle_variant.xml
new file mode 100644
index 00000000..b254ea08
--- /dev/null
+++ b/app/src/main/res/drawable/shuffle_variant.xml
@@ -0,0 +1,8 @@
+<!-- drawable/shuffle_variant.xml -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:height="24dp"
+    android:width="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path android:fillColor="#fff" android:pathData="M17,3L22.25,7.5L17,12L22.25,16.5L17,21V18H14.26L11.44,15.18L13.56,13.06L15.5,15H17V12L17,9H15.5L6.5,18H2V15H5.26L14.26,6H17V3M2,6H6.5L9.32,8.82L7.2,10.94L5.26,9H2V6Z" />
+</vector>
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_main_content.xml b/app/src/main/res/layout/activity_main_content.xml
index 3bb527b7..e3ce7e65 100644
--- a/app/src/main/res/layout/activity_main_content.xml
+++ b/app/src/main/res/layout/activity_main_content.xml
@@ -100,6 +100,13 @@
                 app:fab_label="@string/main_jump_title"
                 app:fab_size="mini"/>
 
+            <com.github.clans.fab.FloatingActionButton
+                android:id="@+id/main_fab_random"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                app:fab_label="@string/main_fab_random"
+                app:fab_size="mini"/>
+
             <com.github.clans.fab.FloatingActionButton
                 android:id="@+id/main_fab_id"
                 android:layout_width="wrap_content"
diff --git a/app/src/main/res/values-ja/strings.xml b/app/src/main/res/values-ja/strings.xml
index db8d893f..710540e2 100644
--- a/app/src/main/res/values-ja/strings.xml
+++ b/app/src/main/res/values-ja/strings.xml
@@ -140,4 +140,5 @@
     <string name="import_old_galleries_folder_not_readable">フォルダを読めません</string>
     <string name="import_old_galleries_notification">旧ギャラリーインポート中…</string>
     <string name="import_old_galleries_notification_done">インポート完了</string>
+    <string name="main_fab_random">ランダムギャラリーを開く</string>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values-ko/strings.xml b/app/src/main/res/values-ko/strings.xml
index fa220ba8..598da2cc 100644
--- a/app/src/main/res/values-ko/strings.xml
+++ b/app/src/main/res/values-ko/strings.xml
@@ -140,4 +140,5 @@
     <string name="import_old_galleries_folder_not_readable">폴더를 읽을 수 없습니다</string>
     <string name="import_old_galleries_notification">이전 버전 갤러리 가져오는 중…</string>
     <string name="import_old_galleries_notification_done">가져오기 완료</string>
+    <string name="main_fab_random">무작위 갤러리 열기</string>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 6dc09043..f21275ad 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -69,6 +69,7 @@
     <string name="main_jump_message">Current page: %1$d\nMaximum page: %2$d</string>
     <string name="main_open_gallery_by_id">Open Gallery by ID</string>
     <string name="reader_failed_to_find_gallery">Failed to open gallery</string>
+    <string name="main_fab_random">Open a random gallery</string>
     <string name="main_fab_cancel">Cancel all downloads</string>
 
     <string name="main_move">Move to page %1$d</string>
diff --git a/app/src/main/res/xml/root_preferences.xml b/app/src/main/res/xml/root_preferences.xml
index 3572ada9..cd28fb7b 100644
--- a/app/src/main/res/xml/root_preferences.xml
+++ b/app/src/main/res/xml/root_preferences.xml
@@ -50,7 +50,8 @@
         <SwitchPreferenceCompat
             app:key="low_quality"
             app:title="@string/settings_low_quality"
-            app:summary="@string/settings_low_quality_summary"/>
+            app:summary="@string/settings_low_quality_summary"
+            app:defaultValue="true"/>
 
     </PreferenceCategory>
 
diff --git a/build.gradle b/build.gradle
index ccd12583..ad7f92dd 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,14 +1,14 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
-    ext.kotlin_version = '1.3.61'
+    ext.kotlin_version = '1.3.72'
     repositories {
         google()
         jcenter()
         maven { url 'https://maven.fabric.io/public' }
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.6.1'
+        classpath 'com.android.tools.build:gradle:3.6.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath "org.jetbrains.kotlin:kotlin-android-extensions:$kotlin_version"
         classpath "org.jetbrains.kotlin:kotlin-serialization:$kotlin_version"
diff --git a/libpupil/build.gradle b/libpupil/build.gradle
index 035a800e..b886c59e 100644
--- a/libpupil/build.gradle
+++ b/libpupil/build.gradle
@@ -6,7 +6,7 @@ dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.3'
-    implementation "org.jetbrains.kotlinx:kotlinx-serialization-runtime:0.14.0"
+    implementation "org.jetbrains.kotlinx:kotlinx-serialization-runtime:0.20.0"
     implementation 'org.jsoup:jsoup:1.12.1'
     testImplementation 'junit:junit:4.13'
 }
diff --git a/libpupil/src/main/java/xyz/quaver/Utils.kt b/libpupil/src/main/java/xyz/quaver/Utils.kt
index 40e8b1b5..c598f697 100644
--- a/libpupil/src/main/java/xyz/quaver/Utils.kt
+++ b/libpupil/src/main/java/xyz/quaver/Utils.kt
@@ -16,10 +16,20 @@
 
 package xyz.quaver
 
+import kotlinx.serialization.UnstableDefault
+import kotlinx.serialization.json.Json
 import java.net.Proxy
 
 var proxy = Proxy.NO_PROXY
 
+@OptIn(UnstableDefault::class)
+var json = Json {
+    isLenient = true
+    ignoreUnknownKeys = true
+    serializeSpecialFloatingPointValues = true
+    useArrayPolymorphism = true
+}
+
 fun availableInHiyobi(galleryID: Int) : Boolean {
     return try {
         xyz.quaver.hiyobi.getReader(galleryID)
diff --git a/libpupil/src/main/java/xyz/quaver/hitomi/common.kt b/libpupil/src/main/java/xyz/quaver/hitomi/common.kt
index f80e15bd..56eea8c0 100644
--- a/libpupil/src/main/java/xyz/quaver/hitomi/common.kt
+++ b/libpupil/src/main/java/xyz/quaver/hitomi/common.kt
@@ -16,7 +16,7 @@
 
 package xyz.quaver.hitomi
 
-import kotlinx.serialization.json.Json
+import xyz.quaver.json
 import xyz.quaver.proxy
 import java.net.URL
 
@@ -24,7 +24,7 @@ const val protocol = "https:"
 
 @Suppress("EXPERIMENTAL_API_USAGE")
 fun getGalleryInfo(galleryID: Int) =
-    Json.nonstrict.parse(
+    json.parse(
         GalleryInfo.serializer(),
         URL("$protocol//$domain/galleries/$galleryID.js").openConnection(proxy).getInputStream().use {
             it.reader().readText()
diff --git a/libpupil/src/main/java/xyz/quaver/hitomi/search.kt b/libpupil/src/main/java/xyz/quaver/hitomi/search.kt
index 927bb41d..b3e65769 100644
--- a/libpupil/src/main/java/xyz/quaver/hitomi/search.kt
+++ b/libpupil/src/main/java/xyz/quaver/hitomi/search.kt
@@ -39,7 +39,7 @@ fun sha256(data: ByteArray) : ByteArray {
     return MessageDigest.getInstance("SHA-256").digest(data)
 }
 
-@UseExperimental(ExperimentalUnsignedTypes::class)
+@OptIn(ExperimentalUnsignedTypes::class)
 fun hashTerm(term: String) : UByteArray {
     return sha256(term.toByteArray()).toUByteArray().sliceArray(0 until 4)
 }
@@ -258,9 +258,9 @@ fun getURLAtRange(url: String, range: LongRange) : ByteArray? {
     }
 }
 
-@UseExperimental(ExperimentalUnsignedTypes::class)
+@OptIn(ExperimentalUnsignedTypes::class)
 data class Node(val keys: List<UByteArray>, val datas: List<Pair<Long, Int>>, val subNodeAddresses: List<Long>)
-@UseExperimental(ExperimentalUnsignedTypes::class)
+@OptIn(ExperimentalUnsignedTypes::class)
 fun decodeNode(data: ByteArray) : Node {
     val buffer = ByteBuffer
         .wrap(data)
@@ -302,7 +302,7 @@ fun decodeNode(data: ByteArray) : Node {
     return Node(keys, datas, subNodeAddresses)
 }
 
-@UseExperimental(ExperimentalUnsignedTypes::class)
+@OptIn(ExperimentalUnsignedTypes::class)
 fun bSearch(field: String, key: UByteArray, node: Node) : Pair<Long, Int>? {
     fun compareArrayBuffers(dv1: UByteArray, dv2: UByteArray) : Int {
         val top = Math.min(dv1.size, dv2.size)
diff --git a/libpupil/src/main/java/xyz/quaver/hiyobi/reader.kt b/libpupil/src/main/java/xyz/quaver/hiyobi/reader.kt
index 945b5ffc..07babd9d 100644
--- a/libpupil/src/main/java/xyz/quaver/hiyobi/reader.kt
+++ b/libpupil/src/main/java/xyz/quaver/hiyobi/reader.kt
@@ -17,14 +17,14 @@
 package xyz.quaver.hiyobi
 
 import kotlinx.serialization.UnstableDefault
-import kotlinx.serialization.json.Json
-import kotlinx.serialization.list
+import kotlinx.serialization.builtins.list
 import org.jsoup.Jsoup
 import xyz.quaver.Code
 import xyz.quaver.hitomi.GalleryFiles
 import xyz.quaver.hitomi.GalleryInfo
 import xyz.quaver.hitomi.Reader
 import xyz.quaver.hitomi.protocol
+import xyz.quaver.json
 import xyz.quaver.proxy
 import java.net.URL
 import javax.net.ssl.HttpsURLConnection
@@ -62,14 +62,14 @@ fun renewCookie() : String {
     }
 }
 
-@UseExperimental(UnstableDefault::class)
+@OptIn(UnstableDefault::class)
 fun getReader(galleryID: Int) : Reader {
     val reader = "https://$hiyobi/reader/$galleryID"
     val url = "https://cdn.hiyobi.me/data/json/${galleryID}_list.json"
 
     val title = Jsoup.connect(reader).proxy(proxy).get().title()
 
-    val galleryFiles = Json.nonstrict.parse(
+    val galleryFiles = json.parse(
         GalleryFiles.serializer().list,
         with(URL(url).openConnection(proxy) as HttpsURLConnection) {
             setRequestProperty("User-Agent", user_agent)