I'll change hats now - answering for GWG and PDFX-ready
1) Is it possible, that an APPE update changes the behaviour how overprints between spot and CMYK are rendered to CMYK only ?
Unfortunately yes. We have reported this to one rip vendor who uses APPE. We cannot say as of now if this was due to a newer version of APPE or RIP vendor specific "features"
2) Why i don´t see an alternate colorspace for GWG green in the object inspector of Acrobat Pro ?
Acrobat object inspector newer showed the alternate color definition of colors defined in either Separation or DeviceN. You need to run any preflight profile (analyse only) and then dig into the result tree: Overview -> Color spaces
3) Why I don´t see slight crosses in Acrobat Pro, when I change the simulated print condition ?
when you change the OI in Acrobat, Acrobat performs an internal conversion from either the embedded OI to the newly defined Output intent or from the defined default CMYK profile if the PDF is missing an OI.
Hence, you will not see any crosses, but an overall shift in color.
Only if you'd replace the embedded OI by any other OI, you'd see your expected change.
4) Does GWG has an mailinglist to aks such questions ? (I didn´t found it on the GWG website...)
You can always send an eMail to either
admin@gwg.org or
info@pdfx-ready.ch, and your eMail will get forwarded accordingly.
Nevertheless, I'd guess that this is a topic everyone on the ECI mailing list is also interested in.