Crash when opening F-Droid on older Android versions

Device OS and version:

Anything less than API level 21.

F-Droid version (in the about screen):

Current master

What did you do? (clear steps if possible)

Started F-Droid

What did you expect to see?

Main screen

What did you see instead?

Continual crashing and restarting of F-droid with the following error:

 ACRA caught a VerifyError for org.fdroid.fdroid
  java.lang.VerifyError: org.fdroid.fdroid.CleanCacheService
      at org.fdroid.fdroid.FDroidApp.onCreate(FDroidApp.java:255)
      at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:969)
      at android.app.ActivityThread.handleBindApplication(ActivityThread.java:3272)
      at android.app.ActivityThread.access$2200(ActivityThread.java:117)
      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:969)
      at android.os.Handler.dispatchMessage(Handler.java:99)
      at android.os.Looper.loop(Looper.java:130)
      at android.app.ActivityThread.main(ActivityThread.java:3683)
      at java.lang.reflect.Method.invokeNative(Native Method)
      at java.lang.reflect.Method.invoke(Method.java:507)
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:864)
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:622)
      at dalvik.system.NativeStart.main(Native Method)

I'm taking a look at it now. In the past I have run into VerifyError s when a class includes bytecode that is not sufficiently guarded by a @TargetApi and relevant runtime check. The CleanCacheService seems find upon first inspection but I'll keep investigating.