Set expiration date for EPUB files

[maryb987654321]

I am a small publisher who would like to offer all of the ebook versions of my list for *free* during the pandemic. However, I cannot afford to do this forever. Is there a way to set an expiration date on an EPUB file? Thank you all and be safe.

[Creamer Training]

Google EPUB DRM. (You will note that some items that come up are about removing DRM.)

Here is some sites with information: 

https://www.kotobee.com/blog/ebook-drm-security-what-how/

https://inkwelleditorial.com/prevent-ebook-theft

Keep in mind that if the viewer can read it, they can probably remove any restrictions. 

[AlphabetSouped]

We're in the same boat. Did you find an easy solution? These suggestions seem pretty complicated.