Hello, Regarding the update for the EX4300 upgrade
In order to upgrade that VC of EX4300 you need to go to a intermediate version like 16 and then you can jump to version 18 .
Request system software add /var/tmp/(Image name ) will be command needed for this proccess.
When you run the command Request system reboot on the master VC all members will be rebooted at once, however, You can make the reboot for one member at the time as long as you specified the member ID at the end of the reboot command.
Also remember to add the Set system services ssh root login-allow as there is a implicit deny for the SSH on root on version 18, this has to be done before the upgrade cause you could lose ssh access if this command is not applied.
Hope this helps.
Please mark "Accept as solution" if this answers your query.
Kudos are appreciated too!
Regards,
Aaron Vindas