this are the different files. in joomla 1.5, that is what the updater upgrades.
however in J 1.6 to 2.5, joomla upgrades work differently and actually override ALL files. so if you want to perform a manual upgrade, these are the files to uprade.

FRONTEND FILES:

  libraries/getid3

  muscol.php

  controller.php

  helpers/helpers.php

  helpers/graphics.php

  models/album.php

  models/artist.php

  models/song.php

  views/songs/tmpl/default_songs.php

  views/album/tmpl/default.php

  views/artist/tmpl/common.php

  views/artist/tmpl/grid_album.php

  views/artist/tmpl/default_album.php

  views/artist/tmpl/detailed_album.php

  views/artists/tmpl/default.php

  views/artists/tmpl/detailed_artist.php

  views/playlist/tmpl/default.php

  views/search/tmpl/songs.php

  views/song/tmpl/default.php

  views/song/tmpl/form.php

  views/song/tmpl/simpleform.php

  views/song/tmpl/form.xml

  views/song/tmpl/simpleform.xml

LANGUAGE:

en-GB.com_muscol.ini

BACKEND FILES

  config.xml

  muscol.php

  controllers/albums.php

  models/album.php

  models/song.php

Thanks Germi..
the database is the same of the version 2.2.2 for Joomla 2.5?

In Facebook I read that the new features are:

-ID3 tag reading and importing
-new comment system
-thumbnail image caching
-and more.

Can you tell me what is "and more", new function or bugfix?

yes DB is the same

"and more" is several small bug fixes, plus some re-writing of Route links to make it more unified and EFFICIENT. is something you don't see at naked eye, but in terms of code is much better
also "and more" is that there is a new SIMPLE FORM layout for songs, for quick and easy upload of a song (to be processed with ID3)

Thanks

ooops...

2.3 is out already?

I found out by browsing the forum, maybe a general notice to the existing users would be nice, or did I miss that?

well, thanks anyway! have been waiting for this three weeks. let me try it out now...

edit: i see that the upgrade is from 2.2.1 to 2.3.0...

can i use this with my 2.2.2 installation, or should i uninstall and install 2.30 instead?

+1