manila 2.1 is what comes on the tp2 stock. 2.5 is a version that was designed for the hd2.
the original 2.1 is what you have on your phone now, the is a new version of 2.1 called htc sense that includes weather clock, home screen animations etc. majority of the rom previews that you see in the upgrades section are the new 2.1(htc sense) NOT 2.5 like many believe. when the carriers release their 6.5 upgrades they will most likely come with the updated version of 2.1 (htc sense)
2.5 does not support landscape in any tabs other that music and photos. that is not a bug or glitch its how it is supposed to be because it was desinged for a phone without a keyboard. the only place that this is affecting is when you are in touch flo3d everywhere else (ie: emails, word, opera etc) you will have landscape like normal
the new version of 2.1 has all the features of 2.5 excpet the shortcuts on the home sceen and some other minor cosmetic differences.
if you have more questions just ask
New Manila 2.1:
Manila 2.5:
