Please check that all the examples in the Workbook work as described. This is possibly a very basic check that nothing fundamental has been upset.
Perhaps you could even recruit a team of keen users to do this check. Instead of releasing on a Friday, and expecting a member of staff to respond to queries over the weekend. Hold off until Monday while volunteers do that simple but time consuming check. Shared between around half a dozen people it would not be too onerous.
For example 'Creating a flood selection' does not do so in the new release 1.7.2. It does work properly in 1.7.2.464 (beta).
A more positive issue. Congratulations of doing rather well in both Amateur Photographer's affordable alternatives to A***e and Practical Photography's Powerful editing suites for under £100. Knocking the opposition for four in both cases is very good. With an optional DAM or Library module I reckon that you would have hit them for six.