Samsung's October 2024 security update is rolling out to the Galaxy S21 lineup. The update hit the Galaxy S24 series in early October, and since then, it has been making its way to older Galaxy S flagships in descending order.
Now, Galaxy S21, S21+, and S21 Ultra owners in some European markets and the USA can grab the October 2024 update on their phones. The rollout began just a few hours ago and shouldn't take long to expand to more countries and regions.
The update can be identified by the build number G99xBXXSDGXI5. It's a purely security-focused update and doesn't bring any other changes or improvements. Once installed, it will bump the security patch level on your Galaxy S21-series phone to October 1, 2024.
The October security patch adds protection against 42 security vulnerabilities discovered in the previous software version. It also addresses an issue discovered in Samsung's Exynos chips, including the Exynos 2100 powering the Galaxy S21 lineup in most countries.
To download the latest update, navigate to your Galaxy S21, S21+, or S21 Ultra's Settings » Software update menu and tap the Download and install button. You can also download Galaxy S21 firmware from the SamMobile archives and install it on the phone using a Windows PC.