This is a very common error you will be seeing while importing an OSB project.
You will be seeing this error when you will try to import a higher version of jar file in your OSB which is installed on lower version. Like a jar file which was created on OSB 11.1.7 and you are trying to import in OSB 11.1.6 or lower version of installation.
To fix this issue, open the jar file using 7-zip or some other tool and edit your ExportInfo file (as highlited in below screen shot) by providing a OSB version you are running with.
Save the change and you will be all set to import the file.