Last month, Microsoft quietly retired the MS DOS prompt in its latest version of Windows 10 released to Microsoft's developer community (known as Windows Insiders). It is being replaced by a ...

Technically, yes, DOS files are in 8+3 Format. However, some versions, like FreeDOS for example, do support LFNs. Running FreeDOS on 808x system is a bit of a slow experience, I assume.

Microsoft and IBM continued to co-develop MS-DOS for many years; the version IBM licensed and sold on its PCs was called PC DOS, though for most of their history the two products were identical.