diff --git a/app/build.gradle b/app/build.gradle
index 4fd94ce0..1c4eaa06 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -13,8 +13,8 @@ android {
         applicationId "xyz.quaver.pupil"
         minSdkVersion 16
         targetSdkVersion 29
-        versionCode 29
-        versionName "4.0"
+        versionCode 30
+        versionName "4.1"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         multiDexEnabled true
         vectorDrawables.useSupportLibrary = true
diff --git a/app/release/output.json b/app/release/output.json
index 0d8ff808..28776d99 100644
--- a/app/release/output.json
+++ b/app/release/output.json
@@ -1 +1 @@
-[{"outputType":{"type":"APK"},"apkData":{"type":"MAIN","splits":[],"versionCode":29,"versionName":"4.0","enabled":true,"outputFile":"app-release.apk","fullName":"release","baseName":"release"},"path":"app-release.apk","properties":{}}]
\ No newline at end of file
+[{"outputType":{"type":"APK"},"apkData":{"type":"MAIN","splits":[],"versionCode":30,"versionName":"4.1","enabled":true,"outputFile":"app-release.apk","fullName":"release","baseName":"release"},"path":"app-release.apk","properties":{}}]
\ No newline at end of file
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 775df295..21f417fa 100644
--- a/app/src/main/java/xyz/quaver/pupil/ui/MainActivity.kt
+++ b/app/src/main/java/xyz/quaver/pupil/ui/MainActivity.kt
@@ -448,7 +448,7 @@ class MainActivity : AppCompatActivity() {
                         startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(getString(R.string.email))))
                     }
                     R.id.main_drawer_kakaotalk -> {
-                        startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(getString(R.string.kakaotalk))))
+                        startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(getString(R.string.discord))))
                     }
                 }
             }
diff --git a/app/src/main/res/menu/activity_main_drawer.xml b/app/src/main/res/menu/activity_main_drawer.xml
index 005695e1..dbe01867 100644
--- a/app/src/main/res/menu/activity_main_drawer.xml
+++ b/app/src/main/res/menu/activity_main_drawer.xml
@@ -53,7 +53,7 @@
                 android:title="@string/main_drawer_group_contact_email"
                 android:icon="@drawable/ic_email"/>
             <item android:id="@+id/main_drawer_kakaotalk"
-                android:title="@string/main_drawer_grouop_contact_kakaotalk"
+                android:title="@string/main_drawer_grouop_contact_discord"
                 android:icon="@drawable/ic_message"/>
         </menu>
     </item>
diff --git a/app/src/main/res/values-ja/strings.xml b/app/src/main/res/values-ja/strings.xml
index cd3270c6..4cf3b38f 100644
--- a/app/src/main/res/values-ja/strings.xml
+++ b/app/src/main/res/values-ja/strings.xml
@@ -66,7 +66,7 @@
     <string name="main_open_gallery_by_id">ギャラリー番号で見る</string>
     <string name="main_open_gallery_by_id_error">エラーが発生しました</string>
     <string name="settings_storage">ストレージ</string>
-    <string name="main_drawer_grouop_contact_kakaotalk">カカオトーク</string>
+    <string name="main_drawer_grouop_contact_discord">ディスコード</string>
     <string name="settings_app_lock">アプリロック</string>
     <string name="settings_app_lock_type">アップロックの種類</string>
     <string name="settings_app_version_title">バージョン</string>
diff --git a/app/src/main/res/values-ko/strings.xml b/app/src/main/res/values-ko/strings.xml
index 7a261d1f..8f3dfa95 100644
--- a/app/src/main/res/values-ko/strings.xml
+++ b/app/src/main/res/values-ko/strings.xml
@@ -66,7 +66,7 @@
     <string name="main_open_gallery_by_id">갤러리 번호로 열기</string>
     <string name="main_open_gallery_by_id_error">갤러리를 찾지 못했습니다</string>
     <string name="settings_storage">저장 공간</string>
-    <string name="main_drawer_grouop_contact_kakaotalk">카카오톡 오픈채팅방</string>
+    <string name="main_drawer_grouop_contact_discord">디스코드햐</string>
     <string name="settings_app_lock">앱 잠금</string>
     <string name="settings_app_lock_type">앱 잠금 종류</string>
     <string name="settings_app_version_title">앱 버전</string>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index e444f882..513ec686 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -7,9 +7,9 @@
     <string name="home_page" translatable="false">http://bit.ly/2EZDClw</string>
     <string name="update" translatable="false">http://bit.ly/2ZlOjXJ</string>
     <string name="help" translatable="false">http://bit.ly/2Z7lNZE</string>
-    <string name="github" translatable="false">https://github.com/tom5079/Pupil-issue/issues/new/choose</string>
+    <string name="github" translatable="false">https://github.com/tom5079/Pupil/</string>
     <string name="email" translatable="false">mailto:pupil.hentai@gmail.com</string>
-    <string name="kakaotalk" translatable="false">https://open.kakao.com/o/gvNrncsb</string>
+    <string name="discord" translatable="false">https://discord.gg/Stj4b5v</string>
     <string name="error_help" translatable="false">http://bit.ly/2KYYhto</string>
 
     <string name="main_settings" translatable="false">Settings</string>
@@ -51,7 +51,7 @@
     <string name="main_drawer_group_contact_homepage">Visit homepage</string>
     <string name="main_drawer_group_contact_github">Visit github</string>
     <string name="main_drawer_group_contact_email">Email me!</string>
-    <string name="main_drawer_grouop_contact_kakaotalk">Kakaotalk</string>
+    <string name="main_drawer_grouop_contact_discord">Discord</string>
 
     <string name="main_menu_sort">Sort</string>
     <string name="main_menu_sort_newest">Newest</string>
diff --git a/libpupil/src/main/java/xyz/quaver/hitomi/reader.kt b/libpupil/src/main/java/xyz/quaver/hitomi/reader.kt
index 89e793a9..355a3a31 100644
--- a/libpupil/src/main/java/xyz/quaver/hitomi/reader.kt
+++ b/libpupil/src/main/java/xyz/quaver/hitomi/reader.kt
@@ -25,7 +25,7 @@ fun webpUrlFromUrl(url: String) = url.replace("/galleries/", "/webp/") + ".webp"
 @Serializable
 data class GalleryInfo(
     val width: Int,
-    val hash: String?,
+    val hash: String? = null,
     val haswebp: Int,
     val name: String,
     val height: Int