Dahua DH-IPC-HDW5849H-ASE-LED firmware on an Empiretech IPC-Color4K-T ?

If you have the international version of the Dahua firmware, yes.

But even if the date of the Dahua firmware is newer, Empiretech may actually still be better. Many times we make suggestions that Empiretech sends to Dahua and we test it and 6-8 months later Dahua may or may not make it available, but when they do it would have their issue date even if it is 8 month old firmware.