Samsung has started testing the One UI 2.1 firmware for Galaxy S9 following Galaxy Note 9.
According to Sam Mobile on the 7th (local time), Samsung Electronics is testing the firmware version G960NKSU3ETE1 for Galaxy S9.
Currently, Galaxy S9 runs in Korea with build number G960NKSU3DTC5. Compared to the test firmware version, you can see that the major release letter has been changed from D to E. This suggests that the Galaxy S9 firmware update under test is a major update.

If the firmware development proceeds smoothly as planned, it is expected to be released to the Galaxy S9 series as early as June. A former Samsung Electronics community official said, “We are preparing an updated version of the One UI 2.1 for the Galaxy S9 with the goal of June.”