Recomended Surf On The Go Firmware

Hi Just purchased a SOTG and the firmware is 1.0.26 (1256) 5-4-15 I found a link here for the the recomended / surfotg 1.0.26 - 1260 and a Stable 1.0.28 - 1274

Which one would should i upgrade to ? Can anyone tell me what has changed in the versions My SOTG now connects to my Verizon Jetpack 6620L by USB but does not recognize my LG G2 or Iphone 5C if i use USB Tether… I read there was a Modem Pack released in a new Firware would this help connect to these devices ? Thanks