TechPowerUp published Intel Releases "Spectre" Hardening Microcode Updates for "Ivy Bridge" thru "Westmere" Architectures A quote from the article:

Intel today released the latest round of CPU micro-code updates for its processors, which expand support for Intel processor microarchitectures ranging all the way back to 1st generation Core "Westmere," and "Lynnfield," and including "Sandy Bridge" and "Ivy Bridge" along the way, at various stages of roll-out (beta, pre-production, and production). This update probably features hardening against "Spectre" variant 4, and perhaps even RSRR (rogue system register read) variant 3A, chronicled in CVE-2018-3640.

 Intel Releases "Spectre" Hardening Microcode Updates for "Ivy Bridge" thru "Westmere" Architectures