FileMaker, Inc. (now Claris International) typically discontinues support and distribution of software versions after a set period. As of now, FileMaker Pro 13 is considered "End of Life" (EOL) legacy software.

Honestly?

FileMaker 13 uses a legacy activation server. Sometimes that server throws a fit with modern SSL certificates. If you get error "-10001" or "Cannot reach server," here is the fix nobody tells you about: