Cleaning… – Marco.org. There are still some odd things about iOS 5. Here's the issue with the cache and tmp directories, which are now cleaned up much more aggressively, causing some applications to have to fetch data from the network much more often (or violate Apple's guidelines and store documents in the cache). This mainly affects offline readers, as their content is, by definition, reconstructable and thus belongs in the cache - but it might be removed there, which makes the whole offline reading absurd. Not good.