Thanks for clarifying this point so clearly here.  All Australian commercial RPAS Operations Manuals have a section referring to software maintenance procedures.  Section 6.2.3 states the requirement to roll back to stable firmware before commercial operations are commenced.  DJI have completely left us all in a very unsafe corner here.  

DJI Thor Posted at 2017-12-27 00:01
Did the drone crash before? The firmware is updated and the mobile device is on the support list, they should work well. May I know the distance that you can fly before the signal drop? Please also make sure that the antennas are placed in the right position. If the issue persists, I suggest that you can contact our support and start a data analysis, we can help to check the data and see if it relates to the drone. Here’s the link to contact us: http://www.dji.com/support.
https://www.youtube.com/watch?v=P7M9JtfVwQE

Hi Thor.
No crashes.  The distance can very from less than 10m away in my back yard to 300m away at the beach\ocean.  I find the more functions I perform, fast gimbal up\down, switching between video & camera\photos, focusing tends to interrupt the signal more.  Once interrupted it can take a while to get back on line again and sometime requires a compete restart.  Yes antennas pointing in the right direction.  As mentioned earlier, no problems before upgrade & big problems after.
Looks like will have to contact support as you mentioned.
Thanks.

Borny Posted at 2017-12-27 19:23
Hi Thor.
No crashes.  The distance can very from less than 10m away in my back yard to 300m away at the beach\ocean.  I find the more functions I perform, fast gimbal up\down, switching between video & camera\photos, focusing tends to interrupt the signal more.  Once interrupted it can take a while to get back on line again and sometime requires a compete restart.  Yes antennas pointing in the right direction.  As mentioned earlier, no problems before upgrade & big problems after.
Looks like will have to contact support as you mentioned.

Thank you for the update and that must be a trouble. Please kindly contact our support for a further help.

DJI Thor Posted at 2017-12-28 00:31
Thank you for the update and that must be a trouble. Please kindly contact our support for a further help.

hi
thanks for that? the update? Do you ask for thanks? ... when you are not doing the right thing, neither as a support nor legally, are you unfortunate

DJI Thor Posted at 2017-12-22 22:54
May I know why do you need to downgrade the firmware? I would like to do the best to help.

Hi Thor ... I don't need to down grade my firmware but I am wondering why the option is no longer there to let me or others do so if we wished? As mentioned previosuly by others, it is surely bad practice to stop people from wanting/needing to do so.

Hi there, the new firmware has optimized some functions of the drone, and it needs to be used with the corresponding version of the app, firmware rollback might cause the unpredicted issue.
And the firmware also updates the No Fly Zone database. Besides, for the concern of the flight safety, for example, some countries have changed the compliance standards, the firmware update has changed it to conform to the new standards, etc.. For many of the reasons, it does not support firmware downgrade. Thank you so much for your support and understanding.