Every few years we see this in the news as a "new" controversy.  Some have even gone so far as to suggest the actual new dates of the star signs--based on astronomy rather than astrology.  Astrology is not the same as Astronomy.  

The actual sun signs have no relevance to the named Constellations in the sky.  In other words, you cannot see the sun signs from astrology in the sky and the fixed star points represented by the Constellations do not correlate to the sun signs.  Astrology is based on divisions in the path of the Sun in a year.  Constellations are fixed points in the sky.  To over-simplify, the relevance of sun sign or zodiac sign dates are based on the changing of the seasons.  The more complex explanation involves mathematics, equinoxes, ephemeris and more.

To generate an astrology chart one must use an Ephemeris.  The gold standard Ephemeris is the Swiss Ephemeris which charts the position of the planets and major stars with in a Astrological Chart which is mathematically created based on the path of the Sun.

Precession is another form within Astrology and one can do a precession of a personal astrology chart.  Even that, however, does not change ones sun sign as it pertains to the astrological chart. 

Also of note is the fact that some give credence to the 13th sign, Ophiuchus (the Serpent Bearer).  The sun passes through this "13th sign" during pretty much the middle third (or a little more) of Sagittarius.  However, my observation has been that this sign has been incorporated into Sagittarius, or acknowledged because each group of 10 degrees within a 30 degree sun sign has its own "pattern" called Orbs of Influence.

So, my position is that no, the dates for the zodiac signs have not changed, at least not yet.