For the most part, Sherlock Holmes has always been portrayed as someone in his prime. There is some variation on age - for instance, Robert Downey Jr. played a relatively young Holmes - but the vast majority of the detective's appearances have been middle-aged.
It makes sense: people expect to see Sherlock at his best, whether it's solving crimes or taking down Moriarty one-on-one.
However, Mr. Holmes is looking to deliver a drastically different take on the world's most famous detective: Ian McKellen is set to start in the titular role, and at 93 years old, it's clear that this version of Holmes is far older than anything that came before it.
Right off the bat, it's clear that this won't be the same version of Sherlock Holmes that everyone has seen before. This is Holmes after a lifetime of detective work, and age has certainly caught up with him. It's a drastically different take on the character. The vast majority of Sherlock Holmes stories focus on solving crimes and apprehending criminals; it's usually not about Holmes' relatively quiet retirement.
Then again, it's hard to argue against Ian McKellen - even if the new portrayal of Holmes isn't up to everyone's personal tastes, McKellen has proven time and time again that he can bring life into just about any performance.
While it's clear that the majority of the film will follow Holmes in his later years, it won't be the only version of the character in the film. The trailer shows Holmes during his prime crime-fighting years, so don't expect the film to be completely devoid of more traditional sleuthing - it just doesn't seem to be the focus this time around.
Mr. Holmes doesn't have a solid U.S. release date quite yet, but seeing how the film already premiered overseas, it's probably not that far off.