Sony Mobile keeps going with pushing firmware updates to its devices. After the Xperia XZ Premium got patched for Spectre and Meltdown, next in line are the Xperia XZ, Xperia XZs and Xperia X Performance that are over two years old. Owners of these three devices should already be receiving the new 47.1.A.12.75 build over the air.
The security update has a February 1, 2018, date and is mostly patching up the software for the CPU vulnerabilities. The firmware does not mention any other changes and is just 120 MB in size. The upgrade should be hitting both dual-SIM and single-SIM versions of the three phones.