Add warning on update check for Android 4.x users

app/src/main/java/eu/kanade/tachiyomi/data/updater/UpdaterJob.kt

@@ -2,6 +2,7 @@ package eu.kanade.tachiyomi.data.updater
 
 import android.app.PendingIntent
 import android.content.Intent
+import android.os.Build
 import android.support.v4.app.NotificationCompat
 import com.evernote.android.job.Job
 import com.evernote.android.job.JobManager
@@ -13,6 +14,11 @@ import eu.kanade.tachiyomi.util.notificationManager
 class UpdaterJob : Job() {
 
     override fun onRunJob(params: Params): Result {
+        // Android 4.x is no longer supported
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            return Result.SUCCESS
+        }
+
         return UpdateChecker.getUpdateChecker()
                 .checkForUpdate()
                 .map { result ->

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsAboutController.kt

@@ -3,6 +3,7 @@ package eu.kanade.tachiyomi.ui.setting
 import android.app.Dialog
 import android.content.Intent
 import android.net.Uri
+import android.os.Build
 import android.os.Bundle
 import android.support.v7.preference.PreferenceScreen
 import android.view.View
@@ -121,6 +122,11 @@ class SettingsAboutController : SettingsController() {
     private fun checkVersion() {
         if (activity == null) return
 
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            activity?.toast("Newer versions of Tachiyomi require Android 5+")
+            return
+        }
+
         activity?.toast(R.string.update_check_look_for_updates)
         releaseSubscription?.unsubscribe()
         releaseSubscription = updateChecker.checkForUpdate()