ml611d.exe      Q138983 PATCH: MASM 6.11d Patch Available       Updates a MASM version 6.11 or 6.11a installation to version 6.11d.
ml614.exe       Q228454 PATCH: MASM 6.14 Patch Available        Updates a MASM version 6.11, 6.11a, 6.11d, 6.12, or 6.13 installation to version 6.14.

MASM 6.14 includes support for the Intel Pentium Pro processor, the Intel MMX architecture, AMD 3D Technology, and Intel Internet Streaming SIMD Extensions.  

Due to changes in the MS-DOS extender used in earlier versions of MASM, MASM 6.14 does not run on Windows 3.1x or MS-DOS. Either Windows NT or Windows 95 is required to run MASM 6.14. If you are working in MS-DOS or Windows 3.1x, you need to continue using version 6.11d. 

Note that you can use MASM 6.14 to develop applications that run under MS-DOS or Windows 3.1x.
