you can download from firefox official website ， they Provide a binary package。
you just run file:firefox.

How do I run the file? What app should I open it with? Or should I somehow use the terminal?

Try this:
It works for both Firefox and Thunderbird. Alternatively you can run firefox as root via
You run it as a normal user, and regularly check the About Firefox from the help menu (it will check for updates if you open it). And if there's an update, you quit Firefox and restart it from terminal with the above command, open About Firefox and let it download and install the update. After that's done you quit Firefox one again and start it as you normally do.

Edited by osomfinch at 2017-2-27 02:41

Thank you for trying to help.
Both options didn't work.
But I installed the Firefox from Deepin Store and the Sync option seems to work now(it didn't before) so I won't bother anymore. Thank you once again.

Edited by savanweylyn at 2017-2-26 19:57

What did you do and what was the error message? For the first option you have to add to /etc/apt/sources.list. To do this open a terminal, type in
copy the line from the above code block and paste it using Shift + Insert. After that's done press CTRL + O (it's an O not a zero), then hit return. Finally close nano with CTRL + X.Or you can use a graphical editor like Gedit. To do this, you have to install the gksu command first withAfter that type inAfter either one, you'll need to run these commands:

This works fine for me.

https://bbs.deepin.org/post/133264#

step 1 ：find file firefox or firefox.bin
step 2 : double-click it

yes i use linux_deepin Official sources,
and it is fine for me.

1. download the latsed vison for Firefox.
2.Unzip the package.
3.Copy all of files to your firefox flolder which your had been installed.
3.Try your new browser.
--------------
You can use this solution for Most program,which is older.