Samsung has started sending out the update to Android 8.0 Oreo to the Galaxy C7 from 2016, specifically the model that was sold primarily in China - SM-C7000. Additionally, a new variant of the Galaxy C5 Pro is tasting Oreo too - we're talking about the one bearing the model number SM-C5018. On the other hand, the Oreo release went out to the SM-C5010 version of the C5 Pro on August 5.
If you own a Galaxy C7 (SM-C7000), the new software version is C7000ZCU3CRH3, while for the C5 Pro (SM-C5018) it's C5018ZMU1CRH2. Interestingly, the C7's update packs the August security fixes (the latest ones, obviously), while the C5 Pro's update settles for the June patches.
As always, these over-the-air rollouts are likely to go out in stages, so don't fret if you own one of the two specific models mentioned above and haven't seen the update notification yet. It should arrive within the next few days or so.