OTA not working

hi there.

I'm using firmware 2.3.0 and sw 2.3.1 and from my android app I can't see any upgrade available.

I followed this howto:
once I run the command, after few seconds, I read "software: 2.3.3" and I see I can update to... 2.3.1!
if I tap one the update, I go back to 2.3.1


is there any way to update firmware to the last available (2.3.3 AFAICS)? 
why am I asket to upgrade to 2.3.1 if I'm running 2.3.3?