La nouvelle UI est toujours en Beta.
Voila le passage que tu as du louper:
"Finally, we encourage you to give the new UI another try. It’s not the default yet, but we intend to make that switch soon, initially leaving the old UI as an option in a beta branch but eventually phasing it out altogether. We will also phase out our 32 bits version as hardware surveys tell us it’s not being used anymore as users have all switched to 64 bits operating systems."
Le système que vous attendez, aller savoir pourquoi d'ailleurs, n'est pas encore finalisé mais arrivera surement quand la nouvelle UI sera au point, ce qui n'est pas chose faite