How much RAM does it have?
The iPhone 5S comes with 1 GB of RAM
Would this be considered a Grade B phone?
This listing would be more of a "Grade C" Grade B would be more in line with our standard Refurbished items and A grade would be listings marked as "Elite Premium"
what phone company can use with these's
A GSM unlocked device will work on any GSM enabled network. This includes AT&T, T-Mobile, etc. It will not work on a CDMA network such Verizon or Sprint.
It says it comes with iOS 8 but will it be able to upgrade to current iOS (11) if wanted too ?
The 5S does support iOS 11, but please be aware some fucntions of iOS 11 of the device will not work since this is an older phone.