How to downgrade sboot sm-j710f 7.0

Dear supporter i got one samsung sm-J710f trying to remove FRP ,,but cant ,,,says DOWNGRADE SBOOt ,,,i have never done it befotre ,,and afraid that set not to be dead by any wrong operation ,,,thats why i make this thread,,,hre is log-:

Log file "C:\Program Files\Octoplus\Octoplus_FRP_Tool\LOG\29-03-2018_12-04-58.log" created (3/29/2018 12:05:03 PM).
INFO : 3/29/2018 12:05:32 PM > Welcome to Octoplus FRP Tool v.1.1.9
INFO : 3/29/2018 12:05:39 PM > Platform: SAMSUNG
INFO : 3/29/2018 12:05:39 PM > Selected model: SM-J710F
INFO : 3/29/2018 12:05:39 PM > Searching for UART interface..
INFO : 3/29/2018 12:05:39 PM > COM7
WARN : 3/29/2018 12:05:39 PM > Connect Samsung Micro UART cable(with 525K resistor), press and hold "Vol-" + "Power" buttons for 15-20 seconds
INFO : 3/29/2018 12:05:39 PM > Searching for device. Please wait...
INFO : 3/29/2018 12:07:17 PM > Phone found.
INFO : 3/29/2018 12:07:17 PM > Rebooting phone in Upload Mode...
INFO : 3/29/2018 12:07:17 PM > OK
WARN : 3/29/2018 12:07:31 PM > Please connect phone to USB cable..
INFO : 3/29/2018 12:07:31 PM > Searching for a phone. Please wait...
INFO : 3/29/2018 12:07:32 PM > OK
INFO : 3/29/2018 12:07:32 PM > Reading data...
INFO : 3/29/2018 12:07:38 PM > Checking operation...
ERROR : 3/29/2018 12:07:38 PM > This version of "sBoot" is not supported, try to downgrade "sBoot"!
ERROR : 3/29/2018 12:07:38 PM > Operation was failed!
INFO : 3/29/2018 12:07:47 PM > Performed by 1.1.9 Software version.
INFO : 3/29/2018 12:07:47 PM >
Log file "C:\Program Files\Octoplus\Octoplus_FRP_Tool\LOG\29-03-2018_12-04-58.log" closed (3/29/2018 12:09:04 PM

Anybody have have any perfect solution to downgrade SBOOT ,,,plz share ,,,,will realy gratefull,,,,Waiting for an affirmative replies,,,