update firmwatre, dashBoard, ATTOiSCSI

hello; thanks in advance for any information

I have a Drobo FS sn = TDB 103370374
probably had its firmware updated ~2012
dash board on apple mac with osx10.10 or osx10.9 dashBoard 2.1.2

-What would be a reliable firmware revision to upgrade to? Things are currently working well and maybe I dont need to upgrade the firmware.
-What is the largest new drive i could mix match install?

-What version dashboard will work well with the older drobo FS and with osx10.10 or osx10.9?

i have Yosemite issues; it does a kernel panic after 20minuites. I noticed 3rd party drivers like com.attotech.driver.ATTOiSCSI (3.4.1b1) <54 7 5 4 3 1>
i do not have scsi drives so can i remove this driver from my osx

We always recommend you have the latest versions of firmware and dashboard installed:

Firmware: 1.2.6
Dashboard: 2.6.7