sorry I didn't post something before, i got sick last week. Anyway i follow a diferent step, that make me able of see a different px4 version when i tried to build.
1 - git checkout v1.7.0
2 - git submodule update --init --recursive
And than i was able to see the px4 version v1.7.0, but i can't find the serial enable and the serial device in sdf file.