From http://www.yam.ch/ :

The YAM developer team is proud to announce that in cooperation with Hyperion Entertainment, the upcoming release of the 'Classic' version of AmigaOS4 (to be released on 30th November) will come with an official sneak preview version of YAM 2.5. This version will be PowerPC native, comes with a fully working default installation and was contributed to allow users of AmigaOS4 to have a look at the current state of the development of YAM 2.5. In addition, we hope to get some more feedback from those users having installed the sneak preview so that we can finalize our development on YAM 2.5 and release a stable version soon. So please stay tuned and enjoy the sneak preview version waiting for you on the 'Classic' release of AmigaOS4.