I just bought a RPi 3 B+ and thought I could easily plug in the SD Card from my RPi 3 B into the new one but the Pi does not boot up. All I get is a blinking PWR LED. I am using the official RPi Power Supply that made no Problem in the RPi 3 B.
I tried 2 different SDs. One with Retro Pie and One with Kodi on it. On the Retro Pie Version I did apt-get update and upgrade just before switching to RPi 3 B.