It seems Sprint is going to try to leap frog to 5g, rolling out a year from now. What's actually required for them to do that ? How much is hardware vs software ? For instance, is a b41 antenna all the hardware required , only the software needs to be updated ? Does it require 8T8R antenna ? If an antenna is updated to 5g, will it still work for 4g or only 5g ?
What Tim said, but also the tower pictured a few posts up appears to have only dual-band antennas (though in your case only PCS is utilized). This Stonewall tower may have had the dual-band antenna replaced with a tri-band (B25/26/41) antenna which is why you see just the addition of the mini-macro unit. It is not the "same antenna." They did in fact replace them, just it was a one-to-one replacement so you likely wouldn't have noticed much difference aside from the mini-macro. These towers it would appear they are going to add a full new antenna for B41. It may be 8T8R, or it may be one of the newer antenna models Tim mentioned.
It's called triband antennas. Many older installations, such as your region, utilized 10 port models which support 800/1.9/2.5 to replace older NV dual band hex ports.
Newer deployments typically utilize the 16 port triband antennas or an addition of a dual band 800/2.5 10 port antenna. The new poles they're adding indicate they're site prepping for likely a new antenna add of some sort.