It’s the circle of life…wait that’s the Lion King. Lifecyle, that a little different.
Microsoft Dynamics GP 2018 and Year-End Update: Lifecycle and Upgrade Services – Microsoft Dynamics GP Community
Microsoft & the GP EcosystemYear-End & 1099Install, Upgrade & AdminGP 2018
Archived post from 2017. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.