There is a Legacy driver that looks to be compatible with many iOptron mounts. This is the one I use because the firmware of my CEM60 is not up to date. So I can't use the CEM60 specific driver.
I guess that at least you can use it
As the driver name indi_ioptronv3_telescope suggests, this is only for mounts that support version 3 of the serial communication protocol. To my knowledge, those are at the moment only the CEM120 and the new CEM70. The other CEMs do use version 2.5 of the protocol, and therefore don't work with the v3 driver.
So I think the driver page needs some documentation update?
For the 'smaller' ioptrons there's the old version of the driver, indi_ieqlegacy_telescope, and the new, refactored indi_ieq_telescope. I have not used the legacy one on a while, but it used to work with my CEM60EC (but doesn't support all features IIRC).