The build 286.4 is available as beta version. The update patch is available in the Download Links post in the "Support Forums / Product Owner's Lounge / Fusion 2.5" forum.
Be careful with this beta version, make backup copies of your MFAs before editing them.
Unlike the alpha versions of the build 286, this beta also contains fixes for the exporters. Big thanks again to the beta testers of the alpha versions.
In case of problem you can reinstall the build 285.8 or any other version (no need to uninstall first, just reinstall the patch of the build you want to reinstall).
If any problem with this version, please post it in the bug box, don't post it in this forum otherwise the developers won't see it, thanks!
PS: the CF 2.5 patch updates all the installed exporters, you do not need to reinstall them.