Intel announced new progress on its efforts to mitigate the Spectre vulnerability today. The company says it has finished "production microcode updates" for its OEM customers and partners for products in its Skylake, Kaby Lake, Coffee Lake, and Skylake-X processors. It also has ready-to-roll updates for partner products built with the Xeon Scalable Processor family and the just-announced Skylake Xeon D line. It's now up to Intel's extensive circle of partners to incorporate those microcode updates into firmware for customers to install.
Intel has also greatly expanded its document outlining microcode update plans for a wide swath of platforms past. According to this document, Broadwell and Haswell microcode designed to mitigate Spectre remains in beta. Although the company isn't listing every Ivy Bridge product as a candidate for a microcode update yet, it is broadly indicating that firmware for at least some of those CPUs is in pre-beta or beta testing, so it seems likely that most systems with one of those CPUs could eventually get a Spectre-banishing update.
The Sandy Bridge family of chips also appears poised to receive some kind of Spectre update in the coming months. Intel indicates that firmware updates for mobile Sandy chips, desktop parts, and Xeons are in beta right now. Older Core CPUs that broadly share the Nehalem microarchitecture, like Bloomfield, Clarksfield, Clarkdale, Gulftown, and Lynnfield, also appear to be in the pipe for updates, although those chips' microcode is in "planning" or "pre-beta" status.
Even if Intel does release microcode for these older CPUs, system builders and buyers alike may be at the mercy of OEMs for final firmware updates (though microcode distribution through Windows updates may remain an option). We'll continue to keep an eye on Intel's progress as the company qualifies further microcode updates for production.