Xiaomi has released a post on Chinese platform Weibo that specifies the launch date for the upcoming Redmi 5 and its plus-sized sibling. Considering how close the launch date is, it's quite surprising that actual details of the devices are anything but confirmed at the moment.
https://www.notebookcheck.net/Xiaomi-Redmi-5-and-Redmi-5-Plus-to-launch-on-December-7.267656.0.html