H4 dropbox with company change eligibility

I have VISA from new company so I am eligible for dropbox, while my spouse has (H4) visa from my old company. Is my spouse eligible for dropbox.

It does not matter, which company the visa is tied to. All that matters is the validity or expiry of the visa and the category. If you fulfil that, you will be eligible. When you try to book appointment, it will ask you the questions and then it will confirm, if you are eligible or not.