I am doing evaluation on Magento 2.x, started with a blank and brand new install of 2.0.4, upgraded to 2.0.7 with no problem. Now I am trying to upgrade to first 2.1 RC2, took forever and did not finish. Reinstalled a brand new empty 2.0.7, and try to run system upgrade to 2.1 RC3. Got Composer Json updated and now I am getting a message of "Update is already in progress" every 2 minutes in the console log. Anybody has some ideas how long this is supposed to take? Got the same thing when updating to RC2, had to terminate the update after a couple of hours. Thanks.