"The "2." was dropped from the version name since Sun had no plans for changes so major and incompatible to justify a Solaris 3.0 release, and was running out of unambigous 2.x numbers (2.10 can be read as either "two point ten" or "two point one zero", one of which implies an upgrade from 2.9, the other does not). (Plus Sun marketing was rumored to want to point out Solaris 7 > NT 5, but then Microsoft renamed NT 5 to Windows 2000 the next week.)"