The logback classic MF specifies import package dependencies of 0.9 on logback core packages. But in the 0.9.15 zip, the logback core is level 0.9.15. This makes bundle resolution difficult under Equinox OSGi. In the same release, it appears that both logback core and logback are running at 0.9.15 and the import-package specification in logback classic MF should probably also specify the same release level since both core and classic are tagged at 0.9.15 instead of 0.9 in the same zip file anyway.