In order to know the compatibility between Xilinx System Generator for DSP and certain release of MATLAB, you also need to know the version of your System Generator for DSP. Refer to this solution article on Xilinx website for MATLAB/Simulink version dependency on System Generator
For example, the latest version Vivado System Generator for DSP 2016.2 is compatible with MATLAB 2014a, 2014b, 2015a and 2015b from The MathWorks (requires Simulink Fixed-Point Toolbox for bus-widths greater than 53 bits). Locate the corresponding system requirements for the version you are using. It seems that on Xilinx’s side, MATLAB R2016b is not yet verified to be compatible with any version of System Generator for DSP at this point.
Also make sure you check out the release notes of MATLAB R2016b for the compatibility that has been tested at the MathWorks’ side. I’m not exactly sure about your workflow, but in case you are using HDL Coder with Xilinx System Generator for DSP, HDL Coder has been tested with Xilinx Vivado Design Suite 2015.4 in MATLAB R2016b.