UK Cabinet Office announced their standard: OASIS Open Document Format 1.2

I'm not sure how much you've been tracking
this, but this is the culmination of length public consultation and review
process, leading to the selection of OASIS ODF 1.2 as the standard for
office documents.

https://www.gov.uk/government/news/open-document-formats-selected-to-meet-user-needs

Details:  https://www.gov.uk/government/publications/open-standards-for-government/sharing-or-collaborating-with-government-documents

Regards,

-Rob