GC2 Extension Panel Upgrade

Just ordered an update cable with the LTE card for my 2GIG GC2 panel.
Was wondering if I have to firmware update my extension panel (bedroom) as well, or just do the firmware upgrade on the main panel?

Version for the GC2 requires the TS1 secondary panel to be at 1.16.

1.16 TS1 is found in the same firmware folder when downloaded. You would need to update both.