Dear friends of FITS, I am pleased to announce that the IAU FITS Working Group has approved the final version of the FITS year-2000 DATExxxx agreement, which I append below. Please note section 7 ("Transition") in the text, in which the IAU-FWG recommends that "..readers should be altered as soon as possible to cope with the new format.." and "..FITS writers should commence writing the new format between 1999-01-01T00:00:00 and 2000-01-01T00:00:00." _All_ FITS reading and writing software must be examined and tested for conformance to these new rules in order to be prepared for full interchange of the new date syntax in 1999. Please circulate copies of this announcement widely, link HTML pages to URL http://www.cv.nrao.edu/fits/documents/standards/year2000.txt and please alert observatory and institute directors, department Chairs, managers of astronomical software groups, etc, to the need to implement this agreement systematically in order to maintain FITS interoperability. Regards, Don Wells (Chair, IAU FITS Working Group)