In Sea-Bird software, is noon on January 1 Julian Day 0.5 or Julian Day 1.5?

In Seasoft-DOS version 4.249 and higher (March 2001 and later), January 1 is Julian Day 1. Therefore, noon on January 1 is Julian Day 1.5. Earlier versions of the software incorrectly defined January 1 as Julian Day 0, so noon on January 1 would appear as Julian Day 0.5.

All release versions of SBE Data Processing correctly identify January 1 as Julian Day 1.