Rev 4 vs Rev 6

[FerroFlux]

I see on xda some people are trying to figure out what the revision numbers on the box mean. Some suggested Rev 4 meant an older batch of z3+ phones that had a Snapdragon 810 vs the 810 v2.1 of Rev 6. Anyone have information on this? 

[Ahmad007]

I Just got my Z3+ Dual and was noticed that it's written Rev 4 on the box.

[kamalaggi]

Mines a rev 5