^ From the wording it does look like they are older than the NX
class since they lack the warp 5 engine. They were never mentioned on ENT but I figured they were to be the warp 7 ships launched after Enterprise
was retired. I know that both the year they came into the fleet & the name were never official but I thought somewhere it said they were launched after the war.
Regardless I'm liking the book & hope the rest of the war is covered someday.