This Knowledgebase article provides information about AMs, AMXs, and Heartbeat.
Heartbeat includes all the general code within Neverfail's software range.
Each Application Module (AM) contains the code to protect one application. For example, if you require Neverfail for IIS, you will need to download from Neverfail's Extranet, Heartbeat and an Application Module for IIS. In some cases, e.g. for SharePoint, you may need to download more than one Application Module. From V5.2.n onwards, the application modules; Neverfail for Exchange, Neverfail for SQL Server, and Neverfail for File Server are downloaded independently of Neverfail Heartbeat.
Prior to V5.2.n, Neverfail for Exchange, Neverfail for SQL Server, and Neverfail for File Server Application Modules were part of the Neverfail Heartbeat download; there was no need to download an Application Module in those cases.
Application Module eXtension
An Application Module eXtension contains the code needed to protect a secondary application, such as anti-virus software or an application that stores data in SQL Server. The Application Module eXtensions are downloaded from the Neverfail Extranet.
Neverfail uses the abbreviation:
AM - for Application Module
AMX - for Application Module eXtension
AM(X) - to mean either or both Application Module or Application Module eXtension