If you're going back and forth on a script between devices, before you switch to the other device, close the script. In the Final Draft desktop program, go to File > Close (and save if prompted). If you're on an iPad or iPhone, touch the left-pointing arrow at the upper left:
This will save, upload and close the open script, so there is no chance that an older version of that script will overwrite it.
If you're working on a script on Device A, that script should not be open on Device B.
- Write on Device A;
- When you're done writing, go to File > Close (Final Draft) or the Scripts List (FD Go / Mobile App);
- Go to Device B, on which either Final Draft is closed or the FD Go / Mobile App is closed or is showing the Scripts List;
- Wait ten seconds to open the script so the sync has time to finish;
- Open the script. It should be the correct version.