Hi,
There is no feature for that in HikaMarket because we don't want to unpublish a product when a vendor modify it.
We have plans to integrate some kind of "history" system in HikaShop which will be used by HikaMarket for a new approval system (I already talked about that several times in the forum) but for the moment that feature is not implement.
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.