My friend and I upgraded our Samsung Galaxy S21FE 5G today with the security patch for October 1, 2024, at the Samsung service facility. My friend has a Snapdragon version, and I have an Exynos. The green line issue has not been noticed by us. According to the Samsung service center customer representative, they will replace the display at no cost even if you noticed a green line problem. The offer to replace the display is valid until December 31, 2024. Ensure that you buy your phone within three years.
