Hello,
It is fully automatic in HikaMarket.
Because you have the "main order" and "sub orders", when a vendor edit an order you can't know if the "main order" will be modified too (because all status need to be the same).
That's why HikaMarket decide to notify the customer depending how the main order is modified.
And regarding the "main order" modification, the checkbox haven't be migrate from the old interface to the new interface which was made for the vendors at the base. It will be fix in the future release.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.