1. Phone looses wifi & Bluetooth connections - problem was in android 7 battery saving profiles, but was solved just by switching to English system language
2. After a week of normal usage built in Phone app had stopped. And app keeps stopping after reset. Clear Cache and Data didn't help. It doesn't crush in airplane mode only

3. Can't copy files from PC to phone using USB. Sending them using Telegram (or other messenger).
Waiting for stable Android 7...