See "New version of libccid: 1.4.25" to get the list of changes.
ReleasesThe CCID driver 1.4.25 was released September, 30th 2016. And the macOS Sierra 10.12.2 upgrade was released December 14, 2016 so 2.5 months later.
That is a good news to see Apple integrating new versions of the CCID driver in "minor" operating system upgrades. It was already the case with macOS El Capitan (see "OS X El Capitan and CCID evolution")