Celebrity Constellation underwent a two-week refurbishment at Chantier Naval de Marseille, including technical maintenance of its propulsion pods, general ship servicing, structural modifications and installation of new balcony structures. Passenger-area improvements included the addition of Qsine specialty restaurant, replacing Ocean Liners, and Top Deck Burger Bar, replacing Mast Grill. The aft upper deck gained the Rooftop Terrace, featuring an outdoor cinema and the Taste of Film dining experience. Penthouse and Royal Suites received upgraded furnishings, carpeting and bathrooms, while the shopping arcade was renovated and a new portrait studio installed. Additional enhancements included RFID electronic stateroom locks and updates to selected public areas. Following the refurbishment, a propulsion-control software issue delayed the ship's scheduled May 26 departure from Barcelona until May 28.

Celebrity Constellation completed an extensive refurbishment at Grand Bahama Shipyard that finished the ship's transformation under Celebrity Cruises' $140 million fleetwide “Solsticizing” program. The project added 66 new staterooms and introduced 107 AquaClass accommodations, including 37 newly constructed cabins and 70 converted from ConciergeClass, while eight Celebrity Suites received new verandas. The ship also gained the Celebrity iLounge, shipwide Wi-Fi, expanded craft-beer offerings in Michael's Club and new conference facilities. Staterooms received new mattresses, while public areas were refreshed with new carpeting, upholstery and color schemes, along with new pool-deck loungers and an upgraded basketball court.

Celebrity Constellation completed an extensive revitalization at Blohm+Voss in Hamburg, becoming the first Millennium-class ship to undergo Celebrity Cruises' “Solsticizing” program. The project introduced Solstice-class venues including Tuscan Grille, Bistro on Five, Café al Bacio and Gelateria, Cellarmasters wine bar and a redesigned ice-topped Martini Bar. Suites received new furniture, flat-screen televisions, upholstery, bedding and carpeting, while staterooms were upgraded with new carpeting, televisions, upholstery and bedding. Public spaces throughout the ship were refreshed with new color schemes, carpeting and upholstery inspired by Celebrity's newer Solstice-class vessels.