The "Equinox Common" can be used on Felix Framework using the "Equinox Supplement" package that provides e.g. "org.eclipse.equinox.log".
The Equinox Logger implements the Logger interface of the OSGi Log Service specification 1.4 https://github.com/eclipse/rt.equinox.framework/blob/63a9e1075ab029c5090a3d50cf52b82f052c62f6/bundles/org.eclipse.osgi/supplement/src/org/eclipse/equinox/log/Logger.java#L23 The "Equinox Supplement" does not usage version constraints at all on its imports: https://github.com/eclipse/rt.equinox.framework/blob/63a9e1075ab029c5090a3d50cf52b82f052c62f6/bundles/org.eclipse.osgi/supplement/META-INF/MANIFEST.MF#L25
