Microsoft is finally adding support for ODF (OpenDocument Format for Office Applications) and Adobe PDF to its Office productivity suite, the company has announced.

Support for ODF and PDF will be included in the software through Microsoft Office Service Pack 2, expected to be out in the first half of 2009, according to Microsoft.

Specifically, the service pack will add file-format support for PDF 1.5, PDF/A and ODF v1.1, as well as XPS (XML Paper Specification). XPS is a similar format to PDF created by Microsoft to rival Adobe's popular document-exchange file format.

PDF 1.5 is a specification created and maintained by Adobe, while PDF/A is the current version of the standard PDF specification maintained by the International Organisation for Standardisation (ISO).

Once the service pack is available and installed on a PC running Office 2007, it will allow users to save documents as ODF, PDF and XPS just as they would any of the current supported file formats in Office. They also can set ODF as the default file format if they so choose. Currently, there are separate plug-ins that allow users to do this now for ODF, and for PDF and XPS, respectively.

Microsoft created its own XML-based file format, OOXML (Office Open XML) for Office 2007. This set into motion a heated rivalry between OOXML and ODF, an open standard supported by companies such as IBM and Sun Microsystems and approved as an ISO standard in May 2006.

Microsoft submitted OOXML to the international standards body Ecma International in November 2005 as an attempt to fast-track it through the ISO. Despite protests and criticisms, that process eventually proved successful on April 1, when the ISO approved OOXML as a standard.

Until now, Microsoft has never said it would natively support ODF, promoting support through software that translates documents between Office file formats and ODF rather than native support.

However, the company has been hammered by the industry - particularly through repeated fines by the European Commission - for its lack of support for interoperability with other companies' products.

Microsoft previously had said it would support PDF in Office 2007, but Adobe, the owner of the specification, blocked that move. As a result, Microsoft said it would pull native PDF support from Office 2007 in June 2006. Adobe has since submitted PDF to the ISO as an open standard. At the same time it pulled PDF support from Office, Microsoft also pulled planned support for XPS.

IBM, an outspoken ODF advocate and critic of OOXML, said in a statement that it supported Microsoft's move, saying there is increased interest in ODF and productivity suites that support it, such as its free Symphony software, which is an Office rival now in beta.