Just over two weeks following the release of OS X Mavericks Developer Preview 4, Apple has seeded the 5th preview to developers via the Mac App Store Software Update tool.

Also released is OS X Mountain Lion 10.8.5 build 12F33. That build comes one week after the previous 10.8.5 seed. Safari 6.1 beta 5 has also been released for Mountain Lion.

The new Mavericks beta brings iBooks app. Full tour here.

If you find anything new, you can let us know at tips@9to5mac.com. We will have a running list of changes in this post (below).

New iPhoto version in Mavericks:

– Major performance enhancements in Mavericks

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