Can you please suggest here,
1.How to check the existing running version in XG firewall?(Steps)
2.What is the downtime required if this is the older one ?
3. What is the impact of up gradation in existing policies or client affect?
go here : https://secure2.sophos.com/en-us/mysophos/my-account/network-protection/firmware-updates.aspx
enter S/N of unit
grab updated FW