1.7.3 has been released as a smaller dot release. 1.7.4 is currently in Beta testing and will be released within the next few weeks with the accompanying release notes.
What do you mean by "smaller dot release"? I'm looking on CCO and the latest CTS version is 18.104.22.168(2) released on May 9. Is there a 1.7.3 somewhere?
I checked in with the CTS SW program manager. CTS 1.7.3 ended up being an internal only build. It was never posted to cisco.com or released to customers. The fixes that went into that branch were incoporated into CTS 1.7.4 that just posted to cisco.com a week or so ago.
Hope that helps a bit,