Welcome Tmiller2!
I would recommend either staying at 11 or upgrade to 12 max, with the latest patches. You can always make a v11 runtime, it will happily run on your v12 series B PVP. We still run v10 and have been using series B PanelViews for months (a year?).
When v12 was released, they removed the ability to make runtimes for v5.x and lower. It was later patched to allow runtimes down to v5. V13 removes the ability to make 5.1 and lower runtimes again, this time, it won't be patched.
Be careful when you make runtimes for v5/5.1/6, they are forced to "never allow conversion".