[Galaxy A3, A5, A7, A8, A9 General] wolfensg:
I have decided to give the Nougat for A3 2016 (A310F) another (and another) chance before returning to Marshmallow but I've had some issues - please let me know do you experience similar problems (Nougat only!).

I've upgraded to Nougat by flashing via Odin DBT code package and went from XEO Marshmallow which did not have any of the described problems.

Was running: Android 7.0, Baseband: A310FXXU3CQE7, Build: NRD90M.A310FXXU3CQE6, Kernel: 3.10.61-11350514

To confirm the below I've reflashed back to 6.0 and flashed 7.0 again (same XEO for 6.0 and same DBT for 7.0) also did factory reset and also added wipe data/cache to the test procedure which helped in couple of cases.

Issues I found with 7.0 so far:

By design:

1. Too small UI elements:

Very small single-line notification slider containing the buttons like enable/disable wi-fi, etc. Previously on Marshmallow and Lollipop it was big enough to handle it without problems. Now (thanks to DreamUX?) it is too small (it is much better on my wife's A510F after Nougat upgrade as the buttons can be way easier pressed without accidentally pressing the button to the left or to the right). This one is quite annoying but probably just because the DreamUX (or whatever it is called) has been designed with "bigger phones" in mind...

2. Flawed Power Saving:

There is absolutely no setting in the OS to set the list of apps that I want to run only in foreground and when entering background should be put to sleep (there is such setting in Marshmallow and I used it to have control over the battery life). This causes the battery life on Nougat to be quite disappointing.

FIX: Flash TWRP (see the TWRP thread for details), did wipe of everything possible. Flash back official 7.0. Currently with normal usage - taken from charger at 06:00 currently 15:40 - battery level decreased from 100% to 88% (previously 8-9 hours on battery after full charge only) I susspect that this may be connected with the software I had installed in the past and some leftovers. So installing 7.0 in cleanest possible way did the trick here.

3. Slow battery charge:

Battery is charging quite slow (location off + wifi off + 3g on + phone not being used (periodically reviewing only the status of charging). Full charge from 30-40% to 100% in c/a 4 hours. Tested wipe data/cache - did not help.

All the time:

1. Crashing Samsung Keyboard (if other used):

When used any other keyboard (tested on Swype and Hacker's Keyboard) from Google Play - everything works fine until I click (be it by accident or intentionally) the emoticon icon (near the send button) while either writing a text message or using any other app where this button is available. The result is Samsung Keyboard (?!) crashing (which is odd as another keyboard is being used at the moment) - after the crash no keyboard is available until selected from the settings General Management\Language and input\Default Keyboard

FIX: Do the wipe of data and cache.

2. VPN not working:

VPN does not work (any attempt to establish PPTP connection fails with the built-in software). Tested wipe data/cache - did not help.

Fixed itself after some time... Now it's working. Either magic or this cannot be tested straight after setting up the OS...

3. Battery drain / decreased life on battery:

Nougat is consuming far more battery than Marshmallow (20% of battery taken in one hour while driving to work (one hour) browsing the web and listening to music compared to 6-8% with Marshmallow). Tests made after wipe of data/cache.

FIX: Flash TWRP (see the TWRP thread for details), did wipe of everything possible. Flash back official 7.0. Currently with normal usage - taken from charger at 06:00 currently 15:40 - battery level decreased from 100% to 88% (previously 8-9 hours on battery after full charge only) I susspect that this may be connected with the software I had installed in the past and some leftovers. So installing 7.0 in cleanest possible way did the trick here.

Often:

1. Stuck "Call" button in UI:

Inability to click "Call" button from the contacts if often calling several contacts (UI seems to lock for 5-15 seconds). To reproduce: Go to the phone app - select contacts, then tap on any contact name (not a picture) - four buttones called "call, message, video call and details" will slide - try tapping "call". Repeat calling several contacts - the UI hangs for couple of seconds making clicking "Call" impossible (home button however works)

WORKAROUND: Swipe finger on the contact to the right of the contact or recently dialled number to start dialling (this always works and does not trigge this bug).

Quite often:

1. Mysterious "installations":

Every couple of hours a notification pops-up that something is downloaded but there it is too quick to notice what was being downloaded, where, etc. It happens regardless if restored to factory defaults (seems to appear also on my wifes A510F after Nougat upgrade). It was not related to apps like messenger or instagram being updated by themselves as this feature was disabled in the settings.

FIX: Do the wipe of data and cache. It seems that the "mysterious downloads" was unsuccessfull attempt to update Android Instant Apps ( https://developer.android.com/topic/instant-apps/index.html )

Rare:

1. Blackout:

The screen turns black. After the restart phone boots up but once started again it defaults to lowest brightness level and need to be adjusted.

FIX: Do the wipe of data and cache.