There’s a few hardmod only bugs in patched Erista units that have been known for ages, though surprisingly nobody’s made anything to take advantage of any of them yet, and I have no idea when or even if somebody will.
For software hacks, 4.1.0 and below currently has full hacks, upto 7.0.1 will eventually have full hacks, and 8.0.x might be able to downgrade to 7.0.x in the future. 8.1.0 and above has zero hope.