diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 39c9a983a6..18268561c9 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -174,9 +174,11 @@ dependencies {
     implementation("org.conscrypt:conscrypt-android:2.5.2")
 
     // Data serialization (JSON, protobuf)
-    val kotlinSerializationVersion = "1.2.2"
+    val kotlinSerializationVersion = "1.3.0-RC"
     implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:$kotlinSerializationVersion")
     implementation("org.jetbrains.kotlinx:kotlinx-serialization-protobuf:$kotlinSerializationVersion")
+
+    // TODO: remove these once they're no longer used in any extensions
     implementation("com.google.code.gson:gson:2.8.7")
     implementation("com.github.salomonbrys.kotson:kotson:2.5.0")
 
diff --git a/app/src/main/java/eu/kanade/tachiyomi/data/backup/legacy/LegacyBackupRestore.kt b/app/src/main/java/eu/kanade/tachiyomi/data/backup/legacy/LegacyBackupRestore.kt
index 19c73228f1..32ab16e873 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/data/backup/legacy/LegacyBackupRestore.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/data/backup/legacy/LegacyBackupRestore.kt
@@ -13,13 +13,12 @@ import eu.kanade.tachiyomi.data.database.models.Chapter
 import eu.kanade.tachiyomi.data.database.models.Manga
 import eu.kanade.tachiyomi.data.database.models.Track
 import eu.kanade.tachiyomi.source.Source
-import kotlinx.serialization.decodeFromString
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.JsonObject
 import kotlinx.serialization.json.decodeFromJsonElement
+import kotlinx.serialization.json.decodeFromStream
 import kotlinx.serialization.json.intOrNull
 import kotlinx.serialization.json.jsonPrimitive
-import okio.buffer
 import okio.source
 import java.util.Date
 
@@ -28,8 +27,8 @@ class LegacyBackupRestore(context: Context, notifier: BackupNotifier) : Abstract
     override suspend fun performRestore(uri: Uri): Boolean {
         // Read the json and create a Json Object,
         // cannot use the backupManager json deserializer one because its not initialized yet
-        val backupObject = Json.decodeFromString<JsonObject>(
-            context.contentResolver.openInputStream(uri)!!.source().buffer().use { it.readUtf8() }
+        val backupObject = Json.decodeFromStream<JsonObject>(
+            context.contentResolver.openInputStream(uri)!!
         )
 
         // Get parser version
diff --git a/app/src/main/java/eu/kanade/tachiyomi/data/backup/legacy/LegacyBackupRestoreValidator.kt b/app/src/main/java/eu/kanade/tachiyomi/data/backup/legacy/LegacyBackupRestoreValidator.kt
index ac6a83bc23..b82544f2af 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/data/backup/legacy/LegacyBackupRestoreValidator.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/data/backup/legacy/LegacyBackupRestoreValidator.kt
@@ -5,9 +5,7 @@ import android.net.Uri
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.backup.AbstractBackupRestoreValidator
 import eu.kanade.tachiyomi.data.backup.legacy.models.Backup
-import kotlinx.serialization.decodeFromString
-import okio.buffer
-import okio.source
+import kotlinx.serialization.json.decodeFromStream
 
 class LegacyBackupRestoreValidator : AbstractBackupRestoreValidator() {
     /**
@@ -19,8 +17,8 @@ class LegacyBackupRestoreValidator : AbstractBackupRestoreValidator() {
     override fun validate(context: Context, uri: Uri): Results {
         val backupManager = LegacyBackupManager(context)
 
-        val backup = backupManager.parser.decodeFromString<Backup>(
-            context.contentResolver.openInputStream(uri)!!.source().buffer().use { it.readUtf8() }
+        val backup = backupManager.parser.decodeFromStream<Backup>(
+            context.contentResolver.openInputStream(uri)!!
         )
 
         if (backup.version == null) {
diff --git a/app/src/main/java/eu/kanade/tachiyomi/source/LocalSource.kt b/app/src/main/java/eu/kanade/tachiyomi/source/LocalSource.kt
index c82b2868db..1c4e8c3cf1 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/source/LocalSource.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/source/LocalSource.kt
@@ -2,7 +2,6 @@ package eu.kanade.tachiyomi.source
 
 import android.content.Context
 import com.github.junrar.Archive
-import com.google.gson.JsonParser
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.source.model.Filter
 import eu.kanade.tachiyomi.source.model.FilterList
@@ -15,8 +14,16 @@ import eu.kanade.tachiyomi.util.lang.compareToCaseInsensitiveNaturalOrder
 import eu.kanade.tachiyomi.util.storage.DiskUtil
 import eu.kanade.tachiyomi.util.storage.EpubFile
 import eu.kanade.tachiyomi.util.system.ImageUtil
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonObject
+import kotlinx.serialization.json.contentOrNull
+import kotlinx.serialization.json.decodeFromStream
+import kotlinx.serialization.json.intOrNull
+import kotlinx.serialization.json.jsonArray
+import kotlinx.serialization.json.jsonPrimitive
 import rx.Observable
 import timber.log.Timber
+import uy.kohesive.injekt.injectLazy
 import java.io.File
 import java.io.FileInputStream
 import java.io.InputStream
@@ -68,6 +75,8 @@ class LocalSource(private val context: Context) : CatalogueSource {
         }
     }
 
+    private val json: Json by injectLazy()
+
     override val id = ID
     override val name = context.getString(R.string.local_source)
     override val lang = ""
@@ -157,16 +166,15 @@ class LocalSource(private val context: Context) : CatalogueSource {
             .flatten()
             .firstOrNull { it.extension == "json" }
             ?.apply {
-                val reader = this.inputStream().bufferedReader()
-                val json = JsonParser.parseReader(reader).asJsonObject
+                val obj = json.decodeFromStream<JsonObject>(inputStream())
 
-                manga.title = json["title"]?.asString ?: manga.title
-                manga.author = json["author"]?.asString ?: manga.author
-                manga.artist = json["artist"]?.asString ?: manga.artist
-                manga.description = json["description"]?.asString ?: manga.description
-                manga.genre = json["genre"]?.asJsonArray?.joinToString(", ") { it.asString }
+                manga.title = obj["title"]?.jsonPrimitive?.contentOrNull ?: manga.title
+                manga.author = obj["author"]?.jsonPrimitive?.contentOrNull ?: manga.author
+                manga.artist = obj["artist"]?.jsonPrimitive?.contentOrNull ?: manga.artist
+                manga.description = obj["description"]?.jsonPrimitive?.contentOrNull ?: manga.description
+                manga.genre = obj["genre"]?.jsonArray?.joinToString(", ") { it.jsonPrimitive.content }
                     ?: manga.genre
-                manga.status = json["status"]?.asInt ?: manga.status
+                manga.status = obj["status"]?.jsonPrimitive?.intOrNull ?: manga.status
             }
 
         return Observable.just(manga)