Most HAWK owners probably won't want to upgrade to version 2.59a becuse this software update is for the BOOT ROM only and only changes one small behavior in the sysex dump receive.
VERSION 2.59a - release notess
Released boot code version 1.99 which includes a small enhancement that ensures that when downloading
an original Korg EX-800 or MK2 sysex dump the bend depth parameter (E85) in all patches are
set to the maximum (63).
However, if you do upgrade the boot ROM, it is then necessary to upgrade to version 2.59a software anyway.
/Mike