I moved my site to a new hosting provider, and DNS propagation is already done.
Now, should I delete all my files in my old hosting
Technically there is no need for deleting the old files for the working of the site from the new location. But if you have sensitive data such as passwords in configuration files, you should delete the files as you will never know if anyone is accessing your data. Also if mails are residing in your old hosting account with password details, it is surely a threat.
Don't need to worry about the files of your old hosting as your old hosts is going to delete them in between the one month after canceling their service.
I think they are not going to keep your files unnecessary using their space.
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