14b appears to be the version in the Itch download section.
Viewing post in Chapter 15 Now Available! comments
No problem! You're not the only one who has asked and I know it's confusing. Just a coincidence with how the builds and chapters have been released. Eventually, the version number will be in sync with the latest chapter, and eventually the version number will be higher (e.g., chapter 16 gets released in two or more builds/versions).