my iphone 6 model no. is starting from M

With Apple's numbering system, "M" would indicate a new unit. However, if you have purchased the phone from a source other than an Apple approved merchant, we have no idea if they may have "refurbished" the phone. Please note that model number is for the US, and possibly Canadian market.

Perhaps. Not necessarily. If you told us the entire model number, we might be able to determine better.

Model numbers starting with M are new ones.

(149796)