You need to rebuild the custom Simscape™ libraries:
Whenever you modify the source files.
For use on each platform. Textual component files are platform-independent,
but Simscape blocks are not. If you (or your customers) run MATLAB® on multiple platforms, generate a separate version of custom block
libraries for each platform by running the ssc_build or
ssc_mirror command on this platform.
For use with each new version of Simscape software. Every time you or your customers upgrade to a new
release, you or they have to run ssc_clean and then rebuild
the custom block libraries. For information on how to protect your proprietary
source code when sharing the Simscape files with customers, see Using Source Protection for Simscape Files.