If you have a Pentium III, for example, you may no longer be able to install Win7 Monthly Rollups or Security-only patches, in spite of Microsoft’s promise to support you until January 2020. It’s all about SSE2 and some retroactively fudged documentation. Will anybody notice?
If your PC doesn’t run Streaming Single Instructions Multiple Data (SIMD) Extensions 2, you apparently won’t be getting any more Win7 patches. At least, that’s what I infer from some clandestine Knowledge Base documentation changes made in the past few days.
Even though Microsoft says it’s supporting Win7 until January 14, 2020, if you have an older machine — including any Pentium III — you’ve been blocked, and there’s nothing you can do about it.
Microsoft did something like this with Windows XP when it was getting close to end of life.