This week, we had discovered Beta testing firmware for the Galaxy S10 & Note 10 series devices. Now, we can confirm that both devices will participate in the beta testing program for One UI 4 version. The Beta Operation Manager at South Korea has officially confirmed it to the Galaxy S10 users. Also, the other moderator had already confirmed it for Galaxy Note 10 series. As per the previous answer, the beta testing program for these devices will start from December.
As per the official Android 12 schedule, both devices will get stable One UI 4 update in January 2022. The beta program for the users will start in all the selected countries, and the official banner will be posted on Samsung Members app. We will inform you when Samsung open the beta program for Galaxy S10 & Note 10 devices.
Both the devices were also part of One UI 3 beta testing program and received Android 11 update. Samsung has already mentioned these devices will get major updates for three years and this year might be last for them. It is good that Samsung has considered about these old flagship models.