Hspell 0.8 announcement
Release 0.7 was done on December 22, 2003, which was the winter solstice. About half a year later, we were ready to make another release, and decided to make it exactly half a year later, in June 21, 2004, the date of the summer solstice.
The summer solstice is indeed the longest day of the year, meaning it has the most time of daylight.
We also refer to the distance the earth travelled around the sun since the last release. Because the earth travels in an average radius of one Astronomical unit around the sun, and circumference of a circle is 2*PI*r, i.e., half of it is PI*r, the earth travelled approximately PI astronomical units in the 6 months since the last release.