The beta testing of the One UI update for the Samsung Galaxy Z Flip3 completed successfully and the phone is now getting the finalized stable update. Units in Serbia are now getting the F711BXXU2BUKM firmware, which is a stable version of One UI 4.0 on top of Android 12 and, of course, it includes the December security patch. Samsung is likely using Serbia as a soak test ground and should it all go smoothly the rest of the world should receive the notification in the following days. Via
Source: https://www.gsmarena.com/samsung_galaxy_z_flip3_starts_receiving_stable_one_ui_40_update-news-52151.php