Hi Alan,
Currently we do not support Office 365 upgrades in an existing bottle - this also helps keep the installation more stable since quite frequently their updates will break compatibility until we are able to write and push corresponding updates. Office 365 automatically pulls the latest version during an install, so you can just use your existing installer to create a new bottle with the updated version. I would suggest not deleting your existing bottle until you have confirmed that the new installation did not break anything!
Thanks,
Anna