The HN title is unclear, but the point is that this would be the first time programming is taught to all first graders in a country. At least that's what the article's title claim implies: "Computer programming will soon reach all Estonian schoolchildren." The article itself doesn't seem to suggest a mandatory curriculum change at the national level, though.

I'm not sure where to dig up historical curriculums to verify my memory, but I'm fairly certain that programming was a mandatory subject when I was in first grade. I remember the whole class going to the computer lab and using BASIC. Education is not handled at the country level here, so it was unlikely to be country-wide, but the local population served by said school system would exceed the population of Estonia.