If you need to use old apps that might not run on W10 and you are not visiting risky websites or opening strange emails, the risk is minimal and you can continue with the old apps on the old systems.

Some new or newly updated apps might not run on stale systems. I updated a laptop earlier in the week because of this. It was a relatively painless process that required several hours. So far there have not been any ugly surprises. Evidentially, a lot of junk trash files were deleted because there is more free space. W10 might run a little slower, I don’t have a good handle on this yet, but I’m on the path of increasing RAM.

As of Tuesday, the free upgrade was still available, but not well publicized.