The World War 2 Interactive Atlas has always been the odd one out in our range. It mostly appeals to WW2 aficionados and history buffs, since it is a huge collection of historical maps on the largest conflict of the 20th century. Its maps are all linked together and referenced to a timeline of events. In that capacity as a reference work, it installs as a stand-alone product.
But the Atlas also contains tools, templates and symbols to use in Campaign Cartographer, to create similar maps or edit the existing WW2IA maps. This functionality has previously not been usable in CC3+, but a compatibility update makes it available now. If you own WW2IA, you can download it from your registration page.
With WW2IA the last of the add-ons has now been updated to work with CC3+.