Exclamation How Do I convert Antenna's

Just wanted to have a wider assortment available to me when I make my next purchase. Which varients of the S5 will covert to AWS (1700,2100) for Mobilicity in Canada. So far I know the 900h is off the table but what's the 900'.' version with no letter all about and will it and others convert via antenna mod for prop support ?

Sincerely