It does not seems too much since the Tardis design has been changed… It happened when the transition between the Tenth Doctor and the Eleventh Doctor happened, when the Doctor and Amy Pond first met.
Well, it seems the time to some new changes. “On Christmas Day, the Doctor will usher you into a brand new world,” Steven Moffat told in a Radio Times interview. “[There’s] a brand new Tardis: Same old police box, of course, but when you open those magic blue doors…” announces Moffat in the Christmas double issue of Radio Times magazine. ”
The lighting unit from above the Tardis console is adorned with symbols from the Time Lords’ Gallifreyan “alphabet” and is a darker, more serious-looking proposition to its predecessors (perhaps in keeping with the Time Lord’s post-Pond mood at the start of the Christmas episode).
Moffat said: “When you have a genius designer like Michael Pickwoad, and an opportunity like the Tardis, you’d be mad not to bring the two together.”
Pickwoad’s is the third design since Doctor Who relaunched in 2005. Both previous versions were by Edward Thomas. The classic 1963 original was by Peter Brachacki.
Over here there are more information about the double issue of Radio Times magazine, the Christmas special episode and other interesting stuff.