End of year copyright dates

Another December, another change of copyright years. I had it set up as <ri;%upyear>, but the editors wanted it changed already in late December. So we replaced that tag with 2020, and will have to do it again in a year.

We're wondering, for next year, is there a better way? The editors are not allowed to touch the formats. Is there a way to set the year change to happen, say, December 20th, rather than on January 1st?