While casual users might have been okay with simpler versions, "Pro Plus" was the heavy hitter. It packed everything Microsoft had to offer at the time:

In the late 2010s, the digital world was shifting toward "renting" software through subscriptions. However, for a specific group of professionals and businesses, the release of Microsoft Office Professional Plus 2019 Go to product viewer dialog for this item.

: Included Skype for Business and Outlook for enterprise-level coordination. Overview of Office 2019 (for IT Pros) - Microsoft Learn

This version was built for the "disconnected" or highly controlled environments—think high-security offices or remote research stations where regular internet check-ins weren't an option. The Core of the Suite