“At a software level, they're all the same device, aren't they. Same software, different case.”

In 2013 for the 50th Anniversary of Doctor Who legendary actor Sir John Hurt was introduced as a mysterious new incarnation of The Doctor... a secret incarnation that came between the Eighth and Ninth Doctors. They fought during the Last Great Time War, hence his title being The War Doctor. 

This sonic screwdriver was a new design that acted as a stylistic bridge between the Classic and Modern era sonic screwdriver props. The original War Doctor sonic screwdriver prop was made from a Character Options “Fourth Doctor” toy with modifications from the BBC props department, adding a red anodized pommel section and an LED light in the top. 

It is currently understood that only one War Doctor prop sonic screwdriver was originally created by production and it has been on public display as part of both official BBC exhibitions, the Doctor Who Experience and Doctor Who: Worlds of Wonder.