During the anti-time future of 2371, the Enterprise was not destroyed at Veridian III, but remained in service for a number of years. Admiral Riker saved the vessel from being decommissioned by making it his personal flagship. In this future, the Enterprise underwent several significant modifications, including the addition of a third nacelle, a cloaking device, and a powerful phaser mounted underneath the saucer section.
Star Trek: The Next Generation - “All Good Things...” (TV, 1993)
For its future variant appearance in "All Good Things..." the 4’ model of the U.S.S. Enterprise-D was endowed with various add-ons, designed in a collaborative effort by Dan Curry and Greg Jein.