I really don't know when this happened since texting and whatsapp seems to be used more and more now a days but a few months ago I noticed I was dropping calls and I thought it was because I was driving thru low reception zones but now that customers are calling me more often, I have noticed that the phone call just drops while talking to them or just get a miss call. One of the AT&T stores near me told me it could be the sim card so we got a new one and no changes were noticed. Then I took the phone to the AT&T service center and they did a whole bunch of tests to it, re flashing it was the last test they did because I could have gotten a corrupted update to marshmallow via regular update (their word). Nothing worked and they also disable the "Enhanced LTE Services" claiming AT&T does not really have the capabilities for it yet and while I had my reservations, it has given me another bar in places where I had none or barely 1 now I show 2 but still I hardly ever get to 3 bars on my S6. The tech support guys at the service center are blaming Marshmallow for this issue but I have not been able to find any issues on the internet. Marshmallow may have some issues with the S6 but network problem does not seem to be one of them. Are they full of it and they just don't want to warranty the phone or is there some truth to it? Help me obi-one-kenobi... you're my only hope!