How do I upgrade my yahoo business account from the Classic version to the newer version?

My boss got on my computer a couple of weeks ago and logged into his yahoo account. When I came to try and log into my account it would just keep logging into his even though I kept logging him out. So finally I which mine to the classic version because that was the only way it would allow me to log in. I don’t like how Yahoo Classic functions at all and its making my job very difficult by using it. I just want it back to how it used to be.

There should be a link near the top left to switch to the new version. Once you switch you can not go back.

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