Interesting because I have the dual sim version also and have not receive the update as yet. I was told I have to manually update it through Samsung smart switch and connecting my phone to my laptop. How did you update your device?
what region are you from?I have the same issue.i bought a Internation version S9+ Duos and i only get the 4G not the LTE however on my US version of my S8+ I would get LTE.Was wondering if this might be a problem.