I have 2 devices, my Cherry mobile One G1 running 6.0.1 (an Android One device) and my old Samsung Galaxy Note 8.0 tablet running Jellybean 4.2.2.
When installing updates on my tablet, only the a small part of the update is downloaded this discussion said they're called "delta". But when on my phone, it downloads the entire app all over again. It's fine for small apps, but some games have well over 100mb of data sometimes and it hurts my data allowance to update them.
Is it a feature of MM 6.0.1 or is it a bug on my phone?