SWF in PDF

You should probably start working on an alternative strategy. 

Acrobat relies on the presence of the NPAPI Flash Player to play back SWF content.  When Flash reaches EOL in 2020, we're not going to be updating the NPAPI Flash Player.  This means that the folks that consume your PDF would need a Flash Player installed that will never get another security update, and at some point, the operating system will probably change in a way that ultimately breaks any legacy installations.  So, you could probably get away with it for a minute, but it's really highly dependent on how long you need those PDFs to live for and stuff. 

Depending on what you're doing, you might look at something like Adobe Captivate for interactive learning content or Adobe XD for interactive UI prototyping as a replacement.  If we understood your use-case, we might be able to offer some better recommendations.