According to FileHippo’s release history for Adobe Shockwave Player, Shockwave 12.2.2.172 was released on November 25, 2015.

The official download page for Shockwave confirms that the latest version is 12.2.2.172. Unfortunately, the official release notes for Shockwave show the latest version as 12.2.1.171.

Worse still, Adobe’s Shockwave version checker page tells me this: “Sorry, your computer does not have the latest Shockwave Player installed. Please go to step 2. (Your version:12.2.2.172 Latest Version:12.1.9.159)” It’s trying to tell me that 12.1.9.159 is the latest version (it isn’t) and that the version I’m running (which is in fact the latest version) is both out of date and somehow older than a version which is clearly the older of the two (12.1.9.159 is older than 12.2.2.172).

Hey Adobe: it’s hard enough to keep our software up to date without you sending us mixed messages.