You can copy the CrystalDevHelp.chm file from older revisions into the Help folder of 18.2 and the content will be there (it's still in the combined TOC and index).

Note that you need to make sure you run the Studio "as administrator" the first time after you copy the file in and then access the help index so that the new combined index (the .chw file) is created properly (without Windows UAC virtualizing it).