OnePlus has started sending out a brand new software update to its devices from the first half of 2019 - the OnePlus 7 and 7 Pro. Both of these are now in the process of receiving OxygenOS 10.0.3, and we'll warn you straight from the get-go that this isn't a huge update. It's basically only packing some unnamed improvements for system stability, general bug fixes, and the November 2019 security patch. No, you're not mistaken - we are already in December, almost at the middle of the month in fact. So even with this update, the OnePlus 7 and 7 Pro are still one month behind on the monthly...
Source: https://www.gsmarena.com/oneplus_7_and_7_pro_get_november_security_patch_with_oxygenos_1003-news-40533.php