How to replace the 2 hard drives inside a 2014 G-RAID Thunderbolt 2 - 8TO?

Hey Guys,

Will 2X Seagate 8To or 10To hard drives fit into my 8To G-RAID thunderbolt 2 case ? (Bought in 2014)
Is there a limited size for this type of case ? Do I need a firmware ? And are there any precautions or things to know before replacing the disks ? Finally, what software should I use to format both hard drives ?
Thank you.

No one can help me ?