Found it! You have to modify each upload and select the correct compatibility level from a download. Case solved.
I have uploaded 13 airport sceneries prior to SU5. Tested all of them in SU5 and found problems in two of them only. Those two have been corrected and new versions uploaded. What about the rest that do not need new version uploads? How can I mark them as SU5 compatible? I can not find any information on that...
Currently, the site has left it to the developers to mark addons as compatible. There is some talk of testing all remaining non-compliant addons at some point, but if there are addons out there that, for whatever reason, don't need to be recompiled, or have already BEEN recompiled without resetting the switch, it would be useful for the whole community to know which ones appear to be OK.
Possibly a new listing - just for these, possibly for an administrator (with time to spare between flights) to go through those that appear to be working, and update them to "green".
My suggestion for now is a new thread in this forum called something like "Addons currently marked SU 5 incompatible that actually work fine without crashing the sim", with a set of links below to any addons that you have found that fit this category. You could include an invite for others to add more as they identify wrongly redded addons. That would at least make good redded addons visible to any who use this forum.
How does that sound to you?
You got it.... my misunderstanding. That I have no clue if it's at all possible to mark them. I have been communicating one on one with the creators to ask them if they are and if not will they be soon or at some point. So far, that has been my method.