Is there is a way to save/backup debian installed package ? For example i have installed package 'test version 1.0' and i have installed package 'test version 1.1'. For some reasons i want to restore to 'test version 1.0' but i have not 'test.deb' file 'version 1.0'. How can i backup 'test version 1.0' for restore purpose after if needed.