[raztoki]

1a) no new core updates since 2009. nothing has changed in which would cause that, other than maybe your settings.
1b) believe greying out happens at times for mirror handling once 1 starts above and you have max sim cons higher it will progress to the next download. The rest below become greyed out. once again see 1a) this has always been the case in that version and earlier.

2) JDownloader is a application, and we are not forcing upgrade yet. It will happen shortly, and updates to 0.9 will stop. No fixes can be applied to this version, all fixes are only available in JD2 because of development cycle and old update system doesn't permit it. Please give JD2 a go and see how you go!

3) still undetermined the reason/cause, only speculation as I haven't see any logs or teamviewed. I gave reasons why already for the speculation.

4) not following.