.04 gets released in April (4th month) and .10 gets released in October (10th month) * is then the last two digits of the year of release So the version lets

.04 gets released in April (4th month) and .10 gets released in October (10th month) * is then the last two digits of the year of release So the version lets you know the year and month of release. Edit: Ubuntu is on a 6 month regular release cycle, which is why they are all .04 and .10.