In these boards it's not "5V tolerant". It's actual 5V I/O. EPF10K70. They are obsolete, and so the production part doesn't apply. Solely for hobby stuff.

Fair enough.

What's the software requirement side look like? Intel's website[1; under Legacy Devices] says Quartus II v9.0 was the latest release that could target FLEX 10K devices. Doesn't look like you can download that release anymore, and liable to run into compatibility issues just installing on modern OSs without a VM.

[1] https://fpgasoftware.intel.com/devices/

This only became an issue a few months ago, and it's really annoying if you need older software. Intel/Altera's site used to let you download older releases; it now redirects to a discontinuation notice.

> ...and it's really annoying if you need older software.

Bummer, and a real shame given how seemingly common regressions are in this space. Not my specialization, but anecdotally over a decade or so, I've encountered scenarios on MAX 7000 and Cyclone II (Quartus II v9.0 builds, v10.x breaks), Virtex-7 (Vivado v2018.3 builds, v2019.1 breaks) and Virtex-5 (ISE v14.6 builds, v14.7 breaks).

What do people need 5V for these days?

External stepper motor drivers. eg:

http://leadshine.com/ProductSubType.aspx?type=products&categ...

Driving a stepper directly from FPGA? Why?

Seemed to be more a question of "why 5v at all?", rather than meaning FPGA-specific. ;)

I have a lot of old 8 bit computers, and there's many interesting things you can do with a native 5v FPGA or CPLD there.

I assume interfacing simply with cheap ATMEL and PIC MCUs is another use case.

The university boards can also support 3.3v.

A lot of cheap Atmel micros can run at 3.3v and I think at least some go down to 2.7v.