Welcome!
There have been many changes since v12. Here are a few I found for you. References posted:
v16
+ Support for DSF / DFF / SACD / DSD File Formats
+ Higher quality MP3 decoding
+ The Ultimate Audiophile Solution
MC16 has bit perfect playback. Now with improved support for power
amplifiers, bi-amping, subwoofer calibration, and more. MC's new audio
engine is 64-bit floating point, providing four billion times more
precision than the previous 32-bit engine. Improved quality MP3 decoder
(for times when you don't have a FLAC or APE). Native support for Apple
Lossless (ALAC).
Assists in sound reproduction:
+ Room Correction -- Improved look and operation.
+ Analyzer DSP plugin -- Can show calibrated frequency information per output channel.
http://yabb.jriver.com/interact/index.php?topic=62033.0http://yabb.jriver.com/interact/index.php?topic=65004.0v15
+ Kernel Streaming
http://yabb.jriver.com/interact/index.php?topic=56853.0v14
+ Audiophile -- WASAPI exclusive output using high-end USB DACs
+ Audiophile -- Added ability to play files from memory instead of disk
+ Audiophile -- Support for high end USB DAC's with WASAPI
+ Headphone DSP makes listening more natural and comfortable.
+ Surround Sound output for receivers capable of Dolby Digital or DTS
+ Room Correction -- New in DSP Studio
+ Native support of DirectShow DSP filters
http://wiki.jriver.com/index.php?title=MC14_Featuresv13
+ WASAPI support for high quality playback on Vista and Win 7
http://yabb.jriver.com/interact/index.php?topic=48127.0