From the Document Foundation Blog:
The Document Foundation announces LibreOffice 3.5.4, the fifth version of the free office suite’s 3.5 family. LibreOffice 3.5.4 offers significant performance improvements over the previous versions of the product, which are the combined result of the many code optimizations executed during the last months and the bug and regression chasing activity performed regularly by volunteers and developers. As a result, LibreOffice 3.5.4 is the fastest version of the best free office suite ever, with up to 100% performance gains when opening large files (depending on operating system, hardware configuration and file contents).
For more information, including change log URLs, please see here.