You need Calibre, the LCPL Input plugin (installable from within Calibre) and the DeDRM plugin (needs to be downloaded separately, latest version is here: https://github.com/Satsuoni/DeDRM_tools/releases)

However due to a dubious DMCA request the LCPL plugin in the main DeDRM took has been borked in the official release. Instead you need to download a patch file here: https://gitflic.ru/project/lcpdisliker/dedrmlcpatch Remember DMCA is a US law and does not apply outside the USA, and the patch is perfectly legal and legitimate worldwide.

Simply replace the file "lcpdedrm.py" within the DeDRM zip with the patched version, and then install the plugin within Calibre.

Then you need to add your reading key to the DeDRM plugin (Preferences > Readium LCP ebooks).

Now if you have any LCPL ebooks, merely import the LCPL file in to calibre, and as long as the reading key is correct, DeDRM will decrypt your book in the background. The copy in your library will be DRM free, ready to transfer to your ereader of choice.

Hope that helps. Ebooks.com, one of the biggest ebook sites, is moving to LCPL as of June 2026 which means the existing legal Adobe Digital Editions method is becoming defunct.