MkIII will be upgraded as part of the Advanced Coronal Observing System project. The obsolete PDP 11/44 computer will be replaced during 1997 by machines which can be maintained, and which will support convenient network access. A new low-noise detector channel is being designed for installation in 1998. This channel will complement the current channels which will continue in operation. As part of this upgrade program, current performance limitations of the MkIII are being studied and improvements will be implemented before or at the time of deployment of the low-noise detector channel.