Build 86 can be downloaded from here:

Windows (32-bit): Rainlendar-2.7.b86-32bit.zip
Windows (64-bit): Rainlendar-2.7.b86-64bit.zip
Linux TAR (32-bit): Rainlendar-2.7.b86-i386.tar.bz2
Linux DEB (32-bit): rainlendar2-pro_2.7.b86-1_i386.deb
Linux TAR (64-bit): Rainlendar-2.7.b86-amd64.tar.bz2
Linux DEB (64-bit): rainlendar2-pro_2.7.b86-1_amd64.deb
Mac OS X (Intel): Rainlendar-2.7.b86.dmg

This is beta version! It has not been tested.

The addons for Shadow4 skin 1.6:

www.rainlendar.net/download/1.6/Shadow4-Widgets.r2skin-addon
www.rainlendar.net/download/1.6/Shadow4-Languages.r2skin-addon

Changes:
o Switched back to wxWidgets 2.8.
o Setting a task completed will change the status correctly on Outlook too.
o The url field for events and tasks can now use wiki style link formatting.
o The todo list settings (e.g. the sorting orders) can be changed now from the options too.
o Added support for "exevents" for the xml format skins.
o Added a special "<Hidden>" category which hides the event/task from other windows except the alarm.
o Fixed a crash bug when the calendar is reloaded at the same time the user chose an event from the menu.
o The year, month and day in the keywords can be replaced with YYYY, MM and DD to represent the next date from today. E.g. "[days=YYYY0101]".
o Added possibility to define the height and width for the Shadow4's calendar window from the settings.

Thank you for adding <exevents> Rainy!

In the help file you may want to edit your entry for them.

For your example, you have:

<exevents>
<appearance priority="0" element="bitmap.numbers.lt.blue" align="CENTER" />
</events>

NOTICE, the closer has no "ex".

Good catch. I'll fix that.

Great
It was impossible for me to use beta 85. It just froze when trying to install addons.
Now everything is back to normal. (wxWidgets 2.8???)

I notice I a not able to update password for a network calendar. I believe this was working in the stable release. I can remove and add the calendar again that seem to be working but update the password does not work. I am using it to monitor ics calendar file from a Zimbra server and our password need to be changed every once in a while. This is not specific to build 86, I think it broke a few versions back.
Thanks

Doesn't seem to pull existing descriptions from RTM. Using Deb 32.