2.   Trial version limited to 65,536 pixels 256x256 or 512x128 pixel
Lower than even VGA resolution which is 640x480.

Looking through release notes, this limitation was removed in v1.30a

That is correct and FYI another updated version is to be released in the next week or so.

Big companies like Autodesk abandoned to use of OpenGL in favor of Microsoft DirectX and DirectX3D YEARS AGO and so their software will always run on WINDOWS PC.
Programs that are written using OPENGL (for UNIX/LINUX) would require people to upgrade their graphics card which they cannot do in laptops.
Even new Graphics cards now do not have 32bits drivers anymore. So a Mach3 user cannot use programs written using OPENGL.

1) If you want to run modern software on 15 year old PC's, good luck.

2) Most Processors from the last 10 years have built in graphics that support OpenGL. You don't even need a graphics card to run PixelCNC on most PC's.

3) Mach3 runs fine on 64 bit Operating Systems, as long as you use a motion controller. Tens of thousands of people are doing it.

4) Open GL is still used in a lot of high end CAD and CAM software.

1) If you want to run modern software on 15 year old PC's, good luck.

2) Most Processors from the last 10 years have built in graphics that support OpenGL. You don't even need a graphics card to run PixelCNC on most PC's.

3) Mach3 runs fine on 64 bit Operating Systems, as long as you use a motion controller. Tens of thousands of people are doing it.

4) Open GL is still used in a lot of high end CAD and CAM software.

I know what you are saying.
I am a Chartered IT consultant and I still build and sell computers for PlasmaCAM.
The issue of late versions of OpenGL you will you need Vendor's drivers.
Since most vendors including Intel, Nvidia, AMD no longer supply 32bits drivers, a user of modern PC loaded with 32bits Windows 7 for MACH3 to use the parallel port may only have Microsoft provided drivers which will supports directX12 but NOT OpenGL 3.X or 4.X..
Why  advertise for pixelCNC when there are many other similar programs that will work for a typical MACH3 user?

All i ever said was newbies should checkout  PIXEL CNC because it has a great learning curve for us! If you want to make it into something go ahead.
You don't impress me at all by stating what, who,or where your a member of. That just Tells me you have no time or patience for people trying to learn without drowning in the title that you are shoving at them to put you on your cloud.

Beginners want patience, guidance, and simplicity!
 Suggestion,
Click on the link and contact them in there blog and have this debate, with patience and open mind you might learn something
https://deftware.itch.io/pixelcnc

 PixelCNC supports it and any argument about it using OpenGL meaning that only new computers will work with it is misled and misinformed.

P.S.
I hope your contradictions help your wider audience

Again, developers don't write software to run on old PC's an Operating Systems.

It should run on any PC sold in the last 5 years, and probably even older.

My laptop I am typing on can run
V-CARVE pro 9.5 (latest)
Autodesk Inventor 2015 (what I had NOT LATEST)
Autodesk Autocad 2015 Mechanical (what I had NOT LATEST)
HeeksCNC 1.4 (latest)
FlatCAM latest (latest)
F-engrave latest (latest)
dmap2gcode-0.11 (latest)
GCODE-Spliter (latest)
eagle 7.7 (what I had NOT LATEST)
VISIO 2000 Pro (20 year old)

Since Lazycam can only import DXF version R12, I have ENOUGH software to RUN MACH3.

What is my OpenGL Version? ONLY OPENGL 1.3 according to GLview5.2


Don't get me wrong. I have an I7 Desktop with 16GB RAM running my virtual Pipe organ loading 12GB of 9600bps/24bits samples. I have brand new 64bits Windows 10 PC that can run new CAD Software when I save up money to buy them.

FYI:
I forgot to mention that
I made NC Corrector 4 the gCode editor and live simulator and DXF exporter (from GCode) the default Gcode Editor in MACH3
(sad that it only works 100% if unit is in mm)
Much better than notepad or notepad++ etc usually used in MACH3/4

DOES NOT REQUIRE OPENGL 2.1 too.

FREEWARE (cost $0)