4.6 has updated their licensing schema to check against an API hosted at subsonic.org. This means that the MD5 checksum, while still used, will not activate your subsonic install.
svn co https://subsonic.svn.sourceforge.net/svnroot/subsonic/trunk subsonic
2. Modify subsonic / subsonic-main / src / main / java / net / sourceforge / subsonic / service / SettingsService.java
3. mvn install on the brank root and on subsonic-booter
4. Replace the downloaded subsonic.war and subsonic-booter-with-dependencies.jar with the newly compiled ones. Compilation of subsonic-booter is probably optional. It's just a precaution in case the branch you are compiling is newer than whatever version you downloaded.