What the hell? Quartus with Arria 10 support requires a subscription. Once you stop paying, you cannot upgrade Quartus. So, if I was happy with Quartus 15, stopped paying Altera that yearly fee, now all my Arria 10 devices will keep on degrading, new designs or old, unless I fork over Altera another 4k$ US so I may compile in the latest Quartus prime.
Then again, 1 Arria 10 FPGA goes anywhere from 300$ to 5K$. But still, if I am no longer making PCBs, and I want to preserve my existing Arria 10s, I must pay Altera 4k$.