Jenkins 2.256 and Jenkins 2.257 windows installers are not available because the Microsoft ProductVersion major number and minor number values must be less than 256.

A banner has been proposed for the 2.256 and 2.257 changelog to inform users that they will need to upgrade the war file rather than do a new install.

A stackoverflow article mentions the "DisplayVersion" as a possible way to show the user a meaningful version string without the limitations of the ProductVersion fields.