https://wccftech.com/unlocked-samsung-galaxy-s9-hasnt-received-a-single-security-patch-since-its-release-in-the-us/

The Samsung Galaxy S9 and S9+ have been around on the market for nearly three months. As expected, the devices have received a few OTA updates in the duration—nothing major though, just some bug fixes, optimizations and security patches. However, one variant of the device, in particular, hasn’t received a single update since launch. The device in question is the carrier-unlocked Samsung Galaxy S9 for the US market. It is still running on the February Android security patch, which is unacceptable for a flagship device that costs nearly seven hundred dollars. To make matters worse, Samsung hasn’t revealed any update schedule for the unlocked Galaxy S9

The carrier-unlocked versions of devices are often late to receive updates in the US (and the US only), as was observed with the Galaxy S8 Oreo rollout saga. The company states that carrier-unlocked devices require “additional testing across all networks”, which is why they are late to receive the updates. It is understandable if major OS updates get delayed by a few weeks, but a three-month wait for a security patch is unacceptable.