Back in February, Microsoft announced upcoming updates to two variants of Office, namely Office Long Term Servicing Channel (LTSC) and Office 2021. Both are quite similar in nature with a key difference being that the former is meant for organizational use and the latter is intended for consumers. Both offer five years of mainstream support via a one-time "perpetual" license purchase, but that also means that they won't get any new features or updates until the next perpetual license release. They are primarily intended for organizations and consumers who can't migrate to the cloud to take advantage of Microsoft 365, which gets updated way more frequently.
Microsoft announced a commercial preview of its LTSC releases in April, and now it has announced that Office LTSC has become generally available (GA) to organizations starting today while Office 2021 will hit GA on October 5, which is the same date as Windows 11's general rollout.
Microsoft has emphasized that Microsoft 365's subscription-based system is its preferred direction for the future, it understands that in some scenarios, organizations can't migrate to the cloud or connect certain services to the internet. As such, LTSC releases has more value for them. Although this LTSC release contains performance enhancements and improved accessibility, Microsoft has noted that it cannot take advantage of cloud-driven hybrid security capabilities, AI automation, and real-time collaboration. The company has noted that it will be making "investments" to make it easier for LTSC customers to shift to Microsoft 365 in the future.
Another major change from previous releases is that Office LTSC ships with Teams as part of the installed features, rather than Skype for Business, but Teams is treated differently than other Office apps. Unlike the others, it will continue to get updates continuously over time, but you also only get access to the free version of Teams, since the premium version is licensed separately. You can learn more about managing the free version of Teams here.
Office 2021 is the consumer version of "perpetual" Office and will replace Office 2019 on October 5, 2021. It will be available on Windows and macOS just like Office LTSC. If you're an IT admin at an organization looking to upgrade to Office LTSC generally available today, you can go through Microsoft's deployment instructions here.