The new version offers a host of improvements for both home and business users, especially in terms of ease of use. For example, Quick Connect -- a feature that quickly configures the router to facilitate the NAS server's Internet-based applications -- now supports the setup of more apps, including Cloud Station, DS File, DS Audio, DS Photo+, and the new DS Cloud app.
DS Cloud adds a Dropbox-like sync service for mobile devices. Other improvements available with DSM 4.2 for home users include a revamped Package Center that streamlines management of the server's applications; nearly unlimited accounts and folders for Cloud Station 2, with the file-size limit increased to 10GB; DS Video for iOS, Android, and Windows Phone devices, with support for MKV subtitles; automatic DS Photo+ sync for iOS devices; Video Station-to-browser streaming without a browser plug-in; and Audio Station streaming to Bluetooth speakers.
On top of that, DSM 4.2 includes a few improvements for business users, including the availability of Synology High Availability (SHA) to all x86-based models, helping even smaller businesses to minimize the risk of downtime. Originally, SHA was available only in higher-end enterprise products.
DSM 4.2 also brings support for Amazon's Glacier service for businesses that want more online backup options.
DSM 4.2 works with most existing Synology NAS servers and can be manually downloaded here. Alternatively, you can upgrade the server via the DSM Update function within its Web interface.