I have spotted some changes in the Police Update. I couldn't find the other changes mentioned on other sites like https://thegirlwhogames.wordpress.com/
Minor changes
Welcome to The Sims FreePlay screen has been updated. Rather than showing the SimTown information on the first screen and Sims Update on the other screen, both have been consolidated into one screen. Also The Sims FreePlay's logo is gone. This only requires 1 tap to exit the screen instead of two that was previously required in Day Spa.
Career icons have been changed.
Sims that work in a Career now show a countdown rather than an action bar. Does this change also affect School?
Action name in Simtracker are now in the middle rather than the left. (Needs confirmation)
Have you spotted other changes in the Police Update other than the new Police Profession? Note that I am using an iPod touch so I might suspect that the Welcome to The Sims FreePlay could be different on tablets such as the iPad.