Well, that's why you make full backups you can restore in case of early adoption issues like this. Or, installing the new OS on a separate partition so you can test for possible issues like this, and still have your regular install still there to boot to.
Yes, newer versions of QuickBooks always convert older data. I regularly skip versions and have never had trouble updating account data that was two or three years old. 2013 was the last one I purchased, so I'm going to get 2017 when it's released, which by former release dates, should be before the end of this month.
However, I've never tried updating data, as will be your case, that is six years/versions old. You can contact Intuit and ask.
Intuit has always made the yearly releases of QuickBooks, both Mac and Windows, to be tied very closely to the OS it was developed under. They tend to break the further you get away from its original release date. Intuit also only supports QuickBooks releases for three years, so there will be no more patches of any kind for a 2011 version.