I'm looking for an explanation of the different functionality in versions of a application called VMAC (Verix blah blah blah), also called "comm server", which is used on Verifone payment terminals. I've got terminals with versions 1.7 and 3.3 of VMAC, and I'm unaware of the differences.
If someone is a Verifone expert, it would be helpful to know how much of the communication with the processing host vs the merchant services provider's application.
VMAC stands for Verix Multi App Conductor. VMAC provides a platform for multiple terminal applications to run on a single device. Comm server software is used for communication purpose. Versions mentioned by you are bit older version . Latest version of VMAC available is 3.20.0. Differences between different VMAC versions are like newer versions supports more (and/or Enhanced) features of devices and/or are more robust than previous versions.