What hardware platform are you using?
I would suggest reviewing the "8.2R6.0 PCS Release Notes". Page 4 contains information on supported hardware platforms and upgrade paths.
https://www.pulsesecure.net/download/techpubs/current/837/pulse-connect-secure/pcs/8.2rx/ps-pcs-sa-8.2r6.0-releasenotes.pdf