DSpace 4.0 is now available and can be downloaded from the following  locations:-

1. Sourceforge
2. GitHub

You can also log on to the demo site and have a feel of the release for the three applications, XMLUI, JSPUI and XMLUI Mobile.

New features and improvements

• [new] REST API module based on JAX RS 1.0;
• [new] Request a Copy for files that are not yet available for public downloading;
• [new] DOI Support;
• Discovery formally replaces legacy Search & Browse;
• SWORDv2 module update;
• Improved command line features;
• Support simple embargo in AIP import/export;
• Support running handle server and application container on separate machines;
• Improvements to LDAP Authentication;
• Media filter generates better-looking thumbnails;
• Curation Task for Consuming Web Services;

• [new] A new Bootstrap-based default look and feel
• [new] Integrated PubMed, Arxiv and CrossRef metadata lookup

• Support simple embargo in item display;
• Language switch;
• Mobile Theme matures from beta;

DSpace 4.0 documentation is available here