Samsung has just released an update for the Galaxy J7 Prime in Panama, and the update comes with the November 2018 security patch. This is one of those rare instances where an unannounced security patch has been pushed to a Galaxy device in the previous month. Since it's unannounced, we can't say what security fixes are a part of the package.
November 2018 security patch already here for one Samsung device
The Galaxy J7 Prime is already quite rare in being a budget Galaxy J series phone that has gotten two major OS upgrades. That's something Samsung only offered to mid-range and flagship devices till last year, although it remains to be seen if the mainstream Galaxy J smartphones will get the same treatment in the future. And no, it doesn't look like Samsung will start providing three major OS upgrades to its flagship phones. Even if it does, we won't know until a few months after Samsung has updated its flagships to Android Pie.
If you own a Galaxy J7 Prime, you should be able to download the update from the Settings » Software update menu. It comes with software version G610MUBU3CRJ3 and the complete firmware for the same is also available from our firmware database.