I am running Due Today vn. 188.8.131.528 on my Samsung Galaxy Note 2 with Android 4.3.
I also have the desktop version of Due Today.
I have just realised that the phone is no longer synchronising with ToodleDo (or Desktop Due Today). Changes on the phone don't appear on ToodleDo and changes on ToodleDo do not appear on the phone.
Yet changes on ToodleDo and Desktop Due Today are synchronising with each other just fine.
UPDATE: before resorting to uninstalling and reinstalling Due Today, for no logical reason I changed the Sync Service setting from ToodleDo to Due Today. As I expected, it didn't work and I got a failed sync message. But then after changing the Sync Service back to ToodleDo it is all working fine again. (I think)