In context: OpenDocument is an ISO standardized format for saving word processing documents, spreadsheets, presentations and graphics using ZIP compression and XML metadata. ODF is the native file format for LibreOffice and other free productivity suites, and is also supported by Microsoft's proprietary, commercial suite of Office applications.
ODF developers are still working on the 1.4 release of the popular, open file format for productivity applications, but Microsoft is already adding support for the technology in the latest iteration of its Office tools. As announced on the Microsoft 365 Insider blog, Word, Excel, and PowerPoint have been updated to properly handle ODF 1.4 files and documents.
Microsoft 365 applications available in the Beta Channel will now save natively to the ODF 1.4 format, while ODF 1.3 files can still be opened but only saved as 1.4 docs without the additional features introduced in the latest version. Microsoft is seemingly doing this to improve Office interoperability, but third-party applications built around the ODF ISO standard like LibreOffice are still officially working with ODF 1.3 alone.
LibreOffice cannot yet handle ODF 1.4 features. This means that an ODF 1.4 file saved through the latest Microsoft 365 applications will likely break interoperability rather than improve it in the short term.
Microsoft is, of course, advising Office users to choose the Office Open XML format (.docx, .xlsx, .pptx) when saving Word, Excel, and PowerPoint projects, which already supports the same features offered by the ODF 1.4 format.
The Redmond corporation highlights some of the major improvements included in ODF 1.4, particularly for word processors. The new format adds support for tables in shapes, lists starting from zero, non-overlapping images and shapes, additional writing modes, a new accessibility attribute for "decorative objects" that may be ignored by assistive technologies, and more.
ODF 1.4 spreadsheets saved in Excel can now include color filter settings "with certain restrictions," plus minor improvements in handling error values and text rotation. Finally, PowerPoint presentations can retain slide numbering starting from the number 0, as well as table cell text direction. Decorative objects are supported in ODF 1.4 spreadsheets and presentations, too.
The new document format is supported in the following Word, Excel, and PowerPoint beta versions: 2404 (Build 17531.20078) or later on Windows, and 16.84 (Build 24041420) or later on Mac. Office users unwilling to beta test Microsoft software for free are exempt from the headaches brought by the non-finalized ODF 1.4 format, as they can continue to deal with ODF 1.3 documents and much better interoperability with LibreOffice and other open-source, free suites.