Not necessarily. If you think they are not able to write a strong recommendation then by all means use your previous supervisor. Just make sure you write a note in the optional essay detailing why you did not use your current supervisor.
*Updated 25th July*: Embracing the downtime
Elements of an MBA application series
GMAT (28/02) | Profile (11/03) | Networking / Research (01/04) | Recommendations (30/05) | Essays / Online applications | Interview
My 710 (Q50, V36) Debrief + 740 (Q48, V44) Update:
Please share your profiles for this application season below: