Help update and configuration Router Melon R658

hi I replaced due to failure, the WE1626 router with a Melon R658.
This router has firmware version v2.5.0.
Despite being an open wrt LUCI router, I noticed that it has different settings from the WE1626 router.
I would need to know what is the latest version of the firmware and where to download it, and if it is at least possible to download additional packages, how it was possible to do it with the we1626 router. For these reasons, I have the primary need to download the Italian language package.
Having to connect an ethernet relay card that can be controlled remotely via an android application, I need to set the port foward, the ddns, the port number, etc. on this router. as I did with the previous WE1626 router. Is it possible to have indications? thank you