recommended removing olddriver and relying on the built in Apple FTDI driver (AppleUSBFTDI.kext).
Since 10.9 (Mavericks), OS X has included built-in partial support for some FTDI devices in VCP mode. Starting with 10.11 (El Capitan), Apple's own driver seems to be sufficiently comprehensive that many customers will not need to install FTDI's own VCP unless they wish to use its advanced features such as baud-rate aliasing and configurable latency times.
So version 10.11 onward all should be fine