I already had the newer Diablo Light v2 Rev3.9 so the only benefit for me in upgrading my already upgraded older Diablo was less overheating.
ie my other Diablo Light is a Diablo Light v1 Rev2.2 upgraded to Rev2.3 and now upgraded to v2 Rev4.0.
Gains the Bulsat I2 hack (which no longer AUs, so is reliant on key updates) and Viaccess Canal Sat (the 18 ProviderID: 022610 Key08 channels only), most of TNT Sat (some ECMs changed) and SSR/SRG Swiss (using older ident 023800, so depends how long the card swap from Via2.3 to Via4.0 takes).
Hope this helps your decision.
empb