I have a plugin that allows a user to upload a file; the file is then processed and many xml files are generated and used as source data for the website.
I currently store the xml files in a data directory at plugins/myplugin/data.
However, anytime I user upgrades the plugin, that data will be lost if I leave it there.
What is considered best practice regarding storing files used in this way (not temporary, not media uploads)?
Suggestions?