diff --git a/app/src/androidTest/java/xyz/quaver/pupil/ExampleInstrumentedTest.kt b/app/src/androidTest/java/xyz/quaver/pupil/ExampleInstrumentedTest.kt
index 4f3ce3c8..801d8d34 100644
--- a/app/src/androidTest/java/xyz/quaver/pupil/ExampleInstrumentedTest.kt
+++ b/app/src/androidTest/java/xyz/quaver/pupil/ExampleInstrumentedTest.kt
@@ -25,6 +25,10 @@ import android.util.Log
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.rule.ActivityTestRule
+import kotlinx.serialization.ImplicitReflectionSerializer
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonConfiguration
+import kotlinx.serialization.json.JsonObject
 import org.junit.Assert.assertEquals
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -34,6 +38,7 @@ import xyz.quaver.hiyobi.getReader
 import xyz.quaver.hiyobi.user_agent
 import xyz.quaver.pupil.ui.LockActivity
 import xyz.quaver.pupil.util.getDownloadDirectory
+import java.io.File
 import java.net.URL
 import javax.net.ssl.HttpsURLConnection
 
@@ -63,7 +68,7 @@ class ExampleInstrumentedTest {
 
     @Test
     fun test_doSearch() {
-        val reader = getReader(1426382)
+        val reader = getReader( 1426382)
 
         val data: ByteArray
 
@@ -76,4 +81,31 @@ class ExampleInstrumentedTest {
 
         Log.d("Pupil", data.size.toString())
     }
+
+    @UseExperimental(ImplicitReflectionSerializer::class)
+    @Test
+    fun test_deleteCodeFromReader() {
+        val context = InstrumentationRegistry.getInstrumentation().targetContext
+
+        val json = Json(JsonConfiguration.Stable)
+
+        listOf(
+            getDownloadDirectory(context),
+            File(context.cacheDir, "imageCache")
+        ).forEach { root ->
+            root.listFiles()?.forEach gallery@{ gallery ->
+                val reader = json.parseJson(File(gallery, "reader.json").apply {
+                    if (!exists())
+                        return@gallery
+                }.readText())
+                    .jsonObject.toMutableMap()
+
+                Log.d("PUPILD", gallery.name)
+
+                reader.remove("code")
+
+                File(gallery, "reader.json").writeText(JsonObject(reader).toString())
+            }
+        }
+    }
 }
\ 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 1c48f8e5..31e4fda0 100644
--- a/app/src/main/java/xyz/quaver/pupil/util/update.kt
+++ b/app/src/main/java/xyz/quaver/pupil/util/update.kt
@@ -18,8 +18,13 @@
 
 package xyz.quaver.pupil.util
 
+import android.content.Context
+import kotlinx.serialization.ImplicitReflectionSerializer
 import kotlinx.serialization.json.*
+import xyz.quaver.availableInHiyobi
+import xyz.quaver.hitomi.Reader
 import xyz.quaver.pupil.BuildConfig
+import java.io.File
 import java.net.URL
 
 fun getReleases(url: String) : JsonArray {
@@ -61,4 +66,48 @@ fun getApkUrl(releases: JsonObject) : Pair<String?, String?>? {
         else
             Pair(it.jsonObject["browser_download_url"]?.content, it.jsonObject["name"]?.content)
     }
+}
+
+fun getOldReaderGalleries(context: Context) : List<File> {
+    val oldGallery = mutableListOf<File>()
+
+    listOf(
+        getDownloadDirectory(context),
+        File(context.cacheDir, "imageCache")
+    ).forEach { root ->
+        root.listFiles()?.forEach { gallery ->
+            File(gallery, "reader.json").let { readerFile ->
+                if (!readerFile.exists())
+                    return@let
+
+                Json(JsonConfiguration.Stable).parseJson(readerFile.readText()).jsonObject.let { reader ->
+                    if (!reader.contains("code"))
+                        oldGallery.add(gallery)
+                }
+            }
+        }
+    }
+
+    return oldGallery
+}
+
+@UseExperimental(ImplicitReflectionSerializer::class)
+fun updateOldReaderGalleries(context: Context) {
+
+    val json = Json(JsonConfiguration.Stable)
+
+   getOldReaderGalleries(context).forEach { gallery ->
+       val reader = json.parseJson(File(gallery, "reader.json").readText())
+           .jsonObject.toMutableMap()
+
+       reader["code"] = when {
+           (File(gallery, "images").list()?.
+               all { !it.endsWith("webp") } ?: return@forEach) &&
+                   availableInHiyobi(gallery.name.toInt()) -> json.toJson(Reader.Code.HIYOBI)
+           else -> json.toJson(Reader.Code.HITOMI)
+       }
+
+       File(gallery, "reader.json").writeText(JsonObject(reader).toString())
+   }
+
 }
\ No newline at end of file