diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt
index a38371b13..157379d27 100755
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt
@@ -9,17 +9,13 @@ import eu.kanade.tachiyomi.data.database.models.Manga
 import eu.kanade.tachiyomi.data.database.models.MangaCategory
 import eu.kanade.tachiyomi.data.download.DownloadManager
 import eu.kanade.tachiyomi.data.preference.PreferencesHelper
-import eu.kanade.tachiyomi.source.Source
 import eu.kanade.tachiyomi.source.SourceManager
 import eu.kanade.tachiyomi.source.model.Filter.TriState.Companion.STATE_EXCLUDE
 import eu.kanade.tachiyomi.source.model.Filter.TriState.Companion.STATE_IGNORE
 import eu.kanade.tachiyomi.source.model.Filter.TriState.Companion.STATE_INCLUDE
-import eu.kanade.tachiyomi.source.model.SChapter
 import eu.kanade.tachiyomi.source.model.SManga
 import eu.kanade.tachiyomi.source.online.HttpSource
 import eu.kanade.tachiyomi.ui.base.presenter.BasePresenter
-import eu.kanade.tachiyomi.ui.browse.migration.MigrationFlags
-import eu.kanade.tachiyomi.util.chapter.syncChaptersWithSource
 import eu.kanade.tachiyomi.util.isLocal
 import eu.kanade.tachiyomi.util.lang.combineLatest
 import eu.kanade.tachiyomi.util.lang.isNullOrUnsubscribed
@@ -29,7 +25,6 @@ import exh.favorites.FavoritesSyncHelper
 import exh.util.isLewd
 import java.util.Collections
 import java.util.Comparator
-import java.util.Date
 import rx.Observable
 import rx.Subscription
 import rx.android.schedulers.AndroidSchedulers
@@ -410,87 +405,4 @@ class LibraryPresenter(
 
         db.setMangaCategories(mc, mangas)
     }
-
-    // SY -->
-    fun migrateManga(prevManga: Manga, manga: Manga, replace: Boolean) {
-        val source = sourceManager.get(manga.source) ?: return
-
-        // state = state.copy(isReplacingManga = true)
-
-        Observable.defer { source.fetchChapterList(manga) }
-            .onErrorReturn { emptyList() }
-            .doOnNext { migrateMangaInternal(source, it, prevManga, manga, replace) }
-            .onErrorReturn { emptyList() }
-            .subscribeOn(Schedulers.io())
-            .observeOn(AndroidSchedulers.mainThread())
-            // .doOnUnsubscribe { state = state.copy(isReplacingManga = false) }
-            .subscribe()
-    }
-
-    private fun migrateMangaInternal(
-        source: Source,
-        sourceChapters: List<SChapter>,
-        prevManga: Manga,
-        manga: Manga,
-        replace: Boolean
-    ) {
-        val flags = preferences.migrateFlags().get()
-        val migrateChapters = MigrationFlags.hasChapters(flags)
-        val migrateCategories = MigrationFlags.hasCategories(flags)
-        val migrateTracks = MigrationFlags.hasTracks(flags)
-
-        db.inTransaction {
-            // Update chapters read
-            if (migrateChapters) {
-                try {
-                    syncChaptersWithSource(db, sourceChapters, manga, source)
-                } catch (e: Exception) {
-                    // Worst case, chapters won't be synced
-                }
-
-                val prevMangaChapters = db.getChapters(prevManga).executeAsBlocking()
-                val maxChapterRead =
-                    prevMangaChapters.filter { it.read }.maxBy { it.chapter_number }?.chapter_number
-                if (maxChapterRead != null) {
-                    val dbChapters = db.getChapters(manga).executeAsBlocking()
-                    for (chapter in dbChapters) {
-                        if (chapter.isRecognizedNumber && chapter.chapter_number <= maxChapterRead) {
-                            chapter.read = true
-                        }
-                    }
-                    db.insertChapters(dbChapters).executeAsBlocking()
-                }
-            }
-            // Update categories
-            if (migrateCategories) {
-                val categories = db.getCategoriesForManga(prevManga).executeAsBlocking()
-                val mangaCategories = categories.map { MangaCategory.create(manga, it) }
-                db.setMangaCategories(mangaCategories, listOf(manga))
-            }
-            // Update track
-            if (migrateTracks) {
-                val tracks = db.getTracks(prevManga).executeAsBlocking()
-                for (track in tracks) {
-                    track.id = null
-                    track.manga_id = manga.id!!
-                }
-                db.insertTracks(tracks).executeAsBlocking()
-            }
-            // Update favorite status
-            if (replace) {
-                prevManga.favorite = false
-                manga.date_added = prevManga.date_added
-                prevManga.date_added = 0
-                db.updateMangaFavorite(prevManga).executeAsBlocking()
-            } else {
-                manga.date_added = Date().time
-            }
-            manga.favorite = true
-            db.updateMangaFavorite(manga).executeAsBlocking()
-
-            // SearchPresenter#networkToLocalManga may have updated the manga title, so ensure db gets updated title
-            db.updateMangaTitle(manga).executeAsBlocking()
-        }
-    }
-    // SY <--
 }