The arduino-IDE-included MotorVID28 library tells me: "This Library controls VID28 and equivalent steppermotors (X25, BKA30D-R5, VID29). It can control a stepper either using 6 steps mode or microsteps mode (24 steps) using PWM." Unfortunately it is inaccurate, at least for my X27 with the needle I have. I suspect the rapid accelerations at start/stop throw it off. It is not a strong stepper motor.
The SwitecX25 library at GitHub - clearwater/SwitecX25: Arduino library for Switec X25.168 and friends seems to include code to handle acceleration better and explicitly says: "The rate at which these miniature stepper motors can accelerate is dependent upon the inertia of the needle you are using. You may need to tune the acceleration tables in the library for your needle." As far as I can see, this library seems to work fine for me without tuning.
Edited to add: I'm using the three-pin connection hinted at in the first library above, straight on the Arduino GPIO pins, but with flyback diodes. The SwitecX25 library wants four pin numbers, I simply gave 9,10,10,11. Works like a charm.