Oficial Store mi fit app here only states 3.4.3.
But it seems some people already getting mi fit app 3.4.4 that updates to a new firmware, so is not possible to downgrade to portuguese 1.2.0.8.
Probably someone have to pick up the new firmware and translate, so it is possible to install the custom firmwares without upgrade to the newer in chinese/english only.
I still don't have 3.4.4, if I had I could provide the fw inside, to help translate the new version.