stop press 
noun [mass noun] British
Late news inserted in a newspaper or periodical either at the last moment before printing or after printing has begun (especially as a heading): [as modifier]: stop-press news...
- Last week, our editor slipped in a bit of stop press news on the front page about the long-awaited announcement on collection centres.
- Tuesday, I know, is Press Day and there is an inevitable rush to include the latest ‘stop press' news items and last minute copy changes.
- We can be grateful to the editor, however, for two very interesting and polished papers in this‘stop press' section.