OPN 2.3.3 is mostly a bugfix, but also we have two newest classes for the themes, there do you add in your theme.css.
The newest classes of css are:

.alternatorsubhead {
background: #bfdcfb;
border: solid 1px #A5A5A5; color: #000;
empty-cells: show;
font: 12px Verdana,Arial,Helvetica,sans-serif;
padding: 2px;
}

.listalternatorsubhead {
background: #bfdcfb;
border-bottom: 1px solid #000;
border-left: 1px solid #000;
color: #000;
empty-cells: show;
font: 12px Verdana,Arial,Helvetica,sans-serif;
padding: 4px;
}

The OPN-full version you find here:
OPN 2.3.3

Find the patch here: update 2.3.2 to 2.3.3

openphpnuke-2.3.3-full.* - The whole OPN, with modules and all languages included
openphpnuke-2.3.3-core.* - OPN without the modules
openphpnuke-2.3.3-modules-full.* - Only the modules complete
openphpnuke-2.3.3-module-xxx.* - single modules

If you have already installed 2.3.2 you can use the patch files
openphpnuke-2.3.2-to-2.3.3

We recommend to use the *.tgz or *.tar.bz2 files.
These are much smaller than Zip's. Windows can use theses files without trouble:
*.tgz can be handled with Powerarchiver, Winzip or Winrar.
Powerarchiver or Winrar can handle *.tar.bz2 . A pure " tar for Windows" is available as gnuwin32.

The Changelog you find here

The OPN-Team