Complex sentence: Microsoft described the operating system as being a "service" that will receive non-critical updates over its lifespan, in combination with periodic long-term support milestones for enterprise environments, and the Windows Insider program for public beta testing of future updates.
Split into simpler sentences: Microsoft described the operating system as being a "service" that will receive non-critical updates over its lifespan. Enterprise editions will be capable of using periodic, long-term support milestones to ensure stability, while the Windows Insider program enables beta testing of future updates.