The new update brings system stability and performance improvements along with some bug fixes. The new update is still based on Android Pie 9. The security updates will bump the software version of Oppo R17 and R17 Pro to CPH1879EX_11.C.08 and CPH1877EX_11_C.23 respectively. The update is currently rolling out in some regions. You can manually check for the OTA updates from your device. You have to Go to Settings > tap on System Updates. If there is an update, just click on that and your device will start downloading the update. If there is no update, wait for few more days for the update to come or you can manually download the update file and install it manually.
About Oppo R17 and R17 Pro December 2019 Security patch
Device: Oppo R17 and R17 Pro Type: Global Stable Version: CPH1879EX_11.C.08 and CPH1877EX_11_C.23 Android: 9 Pie Size: above 3GB
Downloads
Oppo R17 Pro – Download (CPH1877EX_11_C.23) Oppo R17 – Download (CPH1879EX_11.C.08)