As per the details, the November 2023 update is currently live for the carrier-locked units of Samsung Galaxy S21 in the US. However, the patch will expand to more region users in the coming days or weeks. You can check the software version below.
Moving toward the changelog, so the latest patch didn’t bring any new features or major changes for the devices. But it assures to offer improved protection against threats and harmful viruses, to maintain device reliability.
In addition, the patch may also upgrade some stock apps and offer enhanced security for an optimized user experience. To take benefit of the latest enhancements install the patch through Settings > Software Update > Download & Install.