diff --git a/app/build.gradle b/app/build.gradle
index 83536419..6704f213 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -38,7 +38,7 @@ android {
         minSdkVersion 16
         targetSdkVersion 30
         versionCode 64
-        versionName "5.1.7"
+        versionName "5.1.7-hotfix1"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         vectorDrawables.useSupportLibrary = true
     }
diff --git a/app/release/output-metadata.json b/app/release/output-metadata.json
index 6ceb8054..e8294f64 100644
--- a/app/release/output-metadata.json
+++ b/app/release/output-metadata.json
@@ -11,7 +11,7 @@
       "type": "SINGLE",
       "filters": [],
       "versionCode": 64,
-      "versionName": "5.1.7",
+      "versionName": "5.1.7-hotfix1",
       "outputFile": "app-release.apk"
     }
   ]
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 50f1b862..5aba4d89 100644
--- a/app/src/main/java/xyz/quaver/pupil/util/misc.kt
+++ b/app/src/main/java/xyz/quaver/pupil/util/misc.kt
@@ -137,5 +137,9 @@ operator fun JsonElement.get(index: Int) =
 operator fun JsonElement.get(tag: String) =
     this.jsonObject[tag]
 
+fun JsonElement.getOrNull(tag: String) = kotlin.runCatching {
+    this.jsonObject.getOrDefault(tag, null)
+}.getOrNull()
+
 val JsonElement.content
     get() = this.jsonPrimitive.contentOrNull
\ No newline at end of file
diff --git a/app/src/main/java/xyz/quaver/pupil/util/update.kt b/app/src/main/java/xyz/quaver/pupil/util/update.kt
index dab3ba5f..c034d074 100644
--- a/app/src/main/java/xyz/quaver/pupil/util/update.kt
+++ b/app/src/main/java/xyz/quaver/pupil/util/update.kt
@@ -285,11 +285,11 @@ fun xyz.quaver.pupil.util.downloader.DownloadManager.migrate() {
                 folder.getChild(".metadata").readText()?.let { Json.parseToJsonElement(it) }
             }.getOrNull()
 
-            val galleryID = metadata?.get("reader")?.get("galleryInfo")?.get("id")?.content?.toIntOrNull()
+            val galleryID = metadata?.getOrNull("reader")?.getOrNull("galleryInfo")?.getOrNull("id")?.content?.toIntOrNull()
                 ?: folder.name.toIntOrNull() ?: return@forEachIndexed
 
             val galleryBlock: GalleryBlock? = kotlin.runCatching {
-                metadata?.get("galleryBlock")?.let { Json.decodeFromJsonElement<GalleryBlock>(it) }
+                metadata?.getOrNull("galleryBlock")?.let { Json.decodeFromJsonElement<GalleryBlock>(it) }
             }.getOrNull() ?: kotlin.runCatching {
                 getGalleryBlock(galleryID)
             }.getOrNull() ?: kotlin.runCatching {
@@ -297,14 +297,14 @@ fun xyz.quaver.pupil.util.downloader.DownloadManager.migrate() {
             }.getOrNull()
 
             val reader: Reader? = kotlin.runCatching {
-                metadata?.get("reader")?.let { Json.decodeFromJsonElement<Reader>(it) }
+                metadata?.getOrNull("reader")?.let { Json.decodeFromJsonElement<Reader>(it) }
             }.getOrNull() ?: kotlin.runCatching {
                 getReader(galleryID)
             }.getOrNull() ?: kotlin.runCatching {
                 xyz.quaver.hiyobi.getReader(galleryID)
             }.getOrNull()
 
-            metadata?.get("thumbnail")?.jsonPrimitive?.contentOrNull?.also { thumbnail ->
+            metadata?.getOrNull("thumbnail")?.jsonPrimitive?.contentOrNull?.also { thumbnail ->
                 val file = folder.getChild(".thumbnail").also {
                     if (it.exists())
                         it.delete()