Which NET+OS for which ME/WIME Module?

I’ve been using NET+OS 6.0 Build that came with my development kit. I can build applications for my older modules with this, but I am running into problems with stability. I know I can’t use NET+OS 6.3 for my old modules, so I can’t take advantage of any of the bug fixes in that version. But I did think I could use 6.0f available from the download site. However, if I build an application with this version, and load it via FTP, the module hangs with both lights solid on. If I use the pin18 reset to reload the original firmware, then try to load an image built with 6.0f via the web interface, I get the error “Unable to update firmware: invalid image header:”.

So, what I would like to know is:

a) What version of NET+OS must I use to build image.bin files for each of my modules (listed below)?

b) Is there one version of NET+OS that will support all versions I have (perhaps with different PLATFORM= lines)?

c) Assuming the answer to b) is no, how can I have multiple versions of NET+OS installed at once (each wants to overwrite cygwin, and each seems tied to a specific version of cygwin, and cygwin doesn’t allow multiple versions to be installed at once)?

d) Do I need the LSK, and if so, how do I get it?

My modules vary in age and have the following part numbers:

PN: (1P)50000866-02 C (Jtag module for development kit - seems to run images from 6.0, 6.0f and 6.3 just fine)
PN: (1P)50000866-01 P (the P is a small sticker covering something else - C maybe? J? Afraid to pull it off.)
PN: (1P)50000866-01 P (the P is as originally printed)
PN: (1P)50000866-01 J
PN: (1P)50000880-02 H (Wi-ME module)
PN: (1P)50000878-03 M (The newest modules I have)

Can anyone from Digi contact me about this? I’m willing to pay for support if I must.