Chris has been chatting online with his parents for years via iChat. Now it doesn't work. Leo says that Apple killed iChat back in OS 10.7. He'll have to use Messages now, which can be a bit confusing. He may have to upgrade to get it to work. Can he go straight OS X El Capitan? Leo says Chris will need to add the app store first. But if it won't download, it may be that his computer isn't compatible. He should still upgrade as far as he can, though.