diff --git a/app/src/main/java/pl/szczodrzynski/edziennik/config/Config.kt b/app/src/main/java/pl/szczodrzynski/edziennik/config/Config.kt
index f065a97e..4da4180e 100644
--- a/app/src/main/java/pl/szczodrzynski/edziennik/config/Config.kt
+++ b/app/src/main/java/pl/szczodrzynski/edziennik/config/Config.kt
@@ -24,7 +24,7 @@ class Config(db: AppDb) : BaseConfig(db) {
     val timetable by lazy { ConfigTimetable(this) }
     val grades by lazy { ConfigGrades(this) }
 
-    var dataVersion by config<Int>(0)
+    var dataVersion by config<Int>(DATA_VERSION)
     var hash by config<String>("")
 
     var lastProfileId by config<Int>(0)
@@ -49,7 +49,8 @@ class Config(db: AppDb) : BaseConfig(db) {
     var widgetConfigs by config<JsonObject> { JsonObject() }
 
     fun migrate(app: App) {
-        if (dataVersion < DATA_VERSION)
+        if (dataVersion < DATA_VERSION || hash == "")
+            // migrate old data version OR freshly installed app (or updated from 3.x)
             ConfigMigration(app, this)
     }
 
diff --git a/app/src/main/java/pl/szczodrzynski/edziennik/config/ProfileConfig.kt b/app/src/main/java/pl/szczodrzynski/edziennik/config/ProfileConfig.kt
index f97c6892..502f0cd6 100644
--- a/app/src/main/java/pl/szczodrzynski/edziennik/config/ProfileConfig.kt
+++ b/app/src/main/java/pl/szczodrzynski/edziennik/config/ProfileConfig.kt
@@ -26,7 +26,7 @@ class ProfileConfig(
     val timetable by lazy { ConfigTimetable(this) }
     val grades by lazy { ConfigGrades(this) }*/
 
-    var dataVersion by config<Int>(0)
+    var dataVersion by config<Int>(DATA_VERSION)
     var hash by config<String>("")
 
     init {
diff --git a/app/src/main/java/pl/szczodrzynski/edziennik/config/utils/AppConfigMigrationV3.kt b/app/src/main/java/pl/szczodrzynski/edziennik/config/utils/AppConfigMigrationV3.kt
index 5af5e1b8..d99de89d 100644
--- a/app/src/main/java/pl/szczodrzynski/edziennik/config/utils/AppConfigMigrationV3.kt
+++ b/app/src/main/java/pl/szczodrzynski/edziennik/config/utils/AppConfigMigrationV3.kt
@@ -16,9 +16,9 @@ import pl.szczodrzynski.edziennik.utils.models.Time
 import kotlin.math.abs
 
 class AppConfigMigrationV3(p: SharedPreferences, config: Config) {
-    init { config.apply {
+    init {
         val s = "app.appConfig"
-        if (dataVersion < 1) {
+        config.apply {
             ui.theme = p.getString("$s.appTheme", null)?.toIntOrNull() ?: 1
             sync.enabled = p.getString("$s.registerSyncEnabled", null)?.toBoolean() ?: true
             sync.interval = p.getString("$s.registerSyncInterval", null)?.toIntOrNull() ?: 3600
@@ -37,9 +37,6 @@ class AppConfigMigrationV3(p: SharedPreferences, config: Config) {
                     NavTarget.HOMEWORK,
                     NavTarget.SETTINGS
             )
-            dataVersion = 1
-        }
-        if (dataVersion < 2) {
             devModePassword = p.getString("$s.devModePassword", null).fix()
             sync.tokenApp = p.getString("$s.fcmToken", null).fix()
             timetable.bellSyncMultiplier = p.getString("$s.bellSyncMultiplier", null)?.toIntOrNull() ?: 0
@@ -86,9 +83,8 @@ class AppConfigMigrationV3(p: SharedPreferences, config: Config) {
                     LoginType.LIBRUS.id -> sync.tokenLibrus = token
                 }
             }
-            dataVersion = 2
         }
-    }}
+    }
 
     private fun String?.fix(): String? {
         return this?.replace("\"", "")?.let { if (it == "null") null else it }
diff --git a/app/src/main/java/pl/szczodrzynski/edziennik/config/utils/ConfigMigration.kt b/app/src/main/java/pl/szczodrzynski/edziennik/config/utils/ConfigMigration.kt
index cbd18e0c..f44d6e56 100644
--- a/app/src/main/java/pl/szczodrzynski/edziennik/config/utils/ConfigMigration.kt
+++ b/app/src/main/java/pl/szczodrzynski/edziennik/config/utils/ConfigMigration.kt
@@ -5,12 +5,9 @@
 package pl.szczodrzynski.edziennik.config.utils
 
 import android.content.Context
+import androidx.core.content.edit
 import pl.szczodrzynski.edziennik.App
-import pl.szczodrzynski.edziennik.BuildConfig
 import pl.szczodrzynski.edziennik.config.Config
-import pl.szczodrzynski.edziennik.ext.HOUR
-import pl.szczodrzynski.edziennik.ui.base.enums.NavTarget
-import pl.szczodrzynski.edziennik.utils.managers.GradesManager.Companion.ORDER_BY_DATE_DESC
 import pl.szczodrzynski.edziennik.utils.models.Time
 import kotlin.math.abs
 
@@ -22,6 +19,9 @@ class ConfigMigration(app: App, config: Config) {
             // migrate appConfig from app version 3.x and lower.
             // Updates dataVersion to level 2.
             AppConfigMigrationV3(p, config)
+            p.edit {
+                remove("app.appConfig.appTheme")
+            }
         }
 
         if (dataVersion < 11) {
@@ -43,5 +43,7 @@ class ConfigMigration(app: App, config: Config) {
 
             dataVersion = 11
         }
+
+        hash = "invalid"
     }}
 }