New iPhone 7 refurbished or not!!!!!!

Hi everybody

i just bought a new iPhone 7

my question is that, if the iPhone 7 product has being produced in 2016 how is it possible to find a new one in year 2019(December)?

do apple inc produces now iPhone 7?

if not, how it was possible for me to buy a new one?

otherwise i think it is refurbished, but i checked other websites and they said that if the first letter of the model number is M it is new(hopefully in this case it was M)

is there any other ways to find out if my phone is refurbished or not?

thank you for your help in advance