How do I use custom fonts for labelling in Geoserver?

You put your custom TTF-fonts in the catalog styles which are located in your data directory.

Then you need to Clear Resource Cache under Server Status so that the font will be loaded by the server!

This is a new functionality from 2.1.x.

Puting my font files (*.ttf) to (...)/geoserver/data/styles still works in version 2.6? I put files there, cleared resources cache and in full list of available fonts they don't exist.