One more time ladies,

The controller hardware is the same for everything.
Some controller boards do not have 6 ribbon cable connectors installed though.

For early Oct merc,sat,jup you had to have October firmware loaded.

When November was first launched you needed November specific firmware and it was not backwards compatible.

Eventually they released firmware that worked with both OCT _OR_ Nov (not both on the same controller)

The nepturd firmware can run OCT28nm, Nov28nm, _OR_ nepturd20nm.
You could plug in Nov28nm _AND_ nepturd20nm at the same time but it will run the nepturds slow.
In other words don't ever mix GE and Ericsson DC/DC converters on a single BTC controller.

Same controller hardware for scrypt but different firmware.
I don't think the tit firmware works with any of the BTC ASICs.

YMMV