The availability of LibreOffice 4.0 Alpha 1 was quietly mentioned in a blog post yesterday.
Among the improvements to LibreOffice 4.0 Alpha 1 is support for attaching comments to document text ranges, extra word boundary characters are now allowed, ink annotations from DOCX/RTF documents can be imported, import/export support for native RTF math expressions, RTF filter now imports old Drawing Objects syntax, and various DOCX improvements.
Other LibreOffice 4.0 work includes improved XLSX load times, an import filter for Microsoft Publisher publications, and much more. Additional LibreOffice 4.0 details are outlined on the Document Foundation Wiki.
The final release of LibreOffice 4.0 is planned for mid-February. The 4.0 release schedule can be found on this Document Foundation web-page. For easy testing, this first alpha release has been uploaded to the LibreOffice pre-releases PPA.