There is substantial demand for a Macintosh eMail client as good as HERMES Mail is for Windows. It is our full intention to satisfy that demand in due time (and use the result as a springboard for future products), but due attention must be drawn to the numerous confounding factors that stand in the way.
The usual bottlenecks (time, manpower, and cost) do not bear examination aside from acknowledgement of their presence, and they will not be further elaborated upon. The total time taken for HERMES Mail/W to be compiled was 2,500 man-hours; please keep this in consideration as you read on.
It is worth noting that for the duration of Eudora's existence, it was a fully separate program (differing in language, schedule, and development team) for every platform. To distinguish the various versions, IBM terminology will be used:
So-called Carbon CFM software, of which Eudora/M is an example, was originally intended to run on Apple Macintosh computers equipped with Power PC microprocessors (G3, G4, G5) and running Mac OS X as their operating system. Unsurprisingly, the ideal use case for Eudora/M would be a Power Mac G5 running OS X Snow Leopard.
At the time of Eudora's discontinuation, though, Apple was moving to the 32-bit Intel architecture (initially, the Core Duo). As a transitional measure, Apple offered support for Carbon CFM software on Intel through an invisible "dynamic translator" known as Rosetta, but this would come at a slight penalty in performance (i.e. speed). 64-bit Intel processors, such as the Core 2 Duo, would not support Rosetta on a hardware level. Software support for Rosetta was removed in OS X Lion.
Carbon Mach-O software, on the other hand, runs on all Intel-equipped Macintosh systems without exception, so long as their operating system is older than OS X Mojave. It is estimated that by the CFM code is migrated to Mach-O, Mojave will have become the second-latest release of OS X.
The task of migrating CFM to Mach-O is simple, but not trivial; while CFM apps can be written and compiled using MetroWerks CodeWarrior or Apple Xcode (developer's choice), Mach-O apps must use Xcode. Eudora has the misfortune of having been created in CodeWarrior.
The current state of the art in Macintosh software is Cocoa (effectively, NeXTStep) 64-bit.
There is an almost universally-held, but incorrect belief that Eudora was a single program with various "front ends" that allowed it to run on Windows, Macintosh, and the now long-discontinued Palm OS; while this may be the prevailing development methodology now, this was not always so, and the truth of the matter is that "Eudora" is a collective name for three software applications with broadly similar user interfaces, but written in different languages to different schedules by separate development teams.