I don’t have a thor 4 pro myself, I just thought of storing this firmware when another member shared a mail.qq.com link to it and I’d already noticed that those links expires quite fast. The only thing I know about the date is what it says in the name of the zipfile.
If you need the BL version, it’s one available in this thread: Zeblaze thor 4 pro stock firmware
If you wish you can also send an email to zeblaze and ask for the firmware and they will probably give you a mail.qq.com link