Hi guys! First of all my english not very good and sorry for that. I am from istanbul.

I bought my mavic in october. When i open it directly ask me for upgrade firmware. I did it. But when i go more then 1 km, it says "rc signal lost, return home"

I did downgrade to fix it. Today i tried it and i went 1.2 km maximum. But what i know is mavic pro can go untill 7 km.

If i upgrade to latest firmware can i go to up to 7km away ?

Please help me..

You are in CE mode so 4 km is the max and that is in best possible places.  The battery is more your limit than distance, that is if you want your Mavic to return home.

Turkey applies CE certification, which means its max distance can reach to 2.5 mi (4 km) in unobstructed, free of interference environment. If the flight distance is not ideal, the obstacles between the drone and RC might block the signal, so you can try to fly the drone in a wide and broad place with less interference.
Also, the position of the antennas makes a great effort, too. Check the position of the antennas for the remote controller. Distance should be greater than height during flight. Please make sure the remote controller’s antennas are positioned parallel to and are pointed towards the aircraft. You can refer to the tutorial below.
Also, update your drone and RC to the consistency or latest version.

DJI Thor Posted at 2018-1-16 18:42
Turkey applies CE certification, which means its max distance can reach to 2.5 mi (4 km) in unobstructed, free of interference environment. If the flight distance is not ideal, the obstacles between the drone and RC might block the signal, so you can try to fly the drone in a wide and broad place with less interference.
Also, the position of the antennas makes a great effort, too. Check the position of the antennas for the remote controller. Distance should be greater than height during flight. Please make sure the remote controller’s antennas are positioned parallel to and are pointed towards the aircraft. You can refer to the tutorial below.
Also, update your drone and RC to the consistency or latest version.

Thank you for the information. Then this problem about firmware version. Even if use the latest firmware i can go up to 2-3 km am i right ?

djiuser_ZvXVwQ5 Posted at 2018-1-17 06:17
Thank you for the information. Then this problem about firmware version. Even if use the latest firmware i can go up to 2-3 km am i right ?

Theoretically, if the firmware of the drone and RC are in the consistency version and the drone performs normally, you can reach the limit that the specs listed above if the environment is good enough.
But if the drone crashed or if there is a hardware issue with the drone, environment interference or other factors that prevent the drone to fly further, you might not be able to go to that distance. It mainly varies from the flight environment.