I use the Mac OS version of Calibre. I currently have version 2.23 installed and I just downloaded version 2.30. Here is the question: On the download page
http://calibre-ebook.com/download_osx it says at the top: "calibre works on OS X 10.7 (Lion) and higher." however, midway down it also says: If you are using OS X older than 10.8 (Mountain Lion), the last version of calibre that will work on your machine is 1.48,..."
Now version 2.23 worked fine on my iMac running Mac OS 10.7.5 (Lion) and I just launched version 2.30 without problems. So shouldn't the second quote above say "If you are using OS X older than 10.7 (Lion)..." ?