At our company we did eventually end up with a hardware dongle. But it helped that it was a HW/SW solution anyway. We just added a few operations that needed to

At our company we did eventually end up with a hardware dongle. But it helped that it was a HW/SW solution anyway. We just added a few operations that needed to go through a hardware module. It was just enough hoops to jump through to hopefully dissuade the casual "pirate". It was an interesting problem anyway. A lot of obvious solutions didn't seem to work, like say just checking a flag in an "if ... else" branch because that can be disassembled and bypassed with a patch. Some functional operations that are critical to the product had to actually go through the hardware... Now looking back we probably over-engineered the heck out of it.