Firstly, I realize that this is a programming Q&A site, and not a place for legal advice....  Just trying to get a basic idea of what the downsides to using an LGPLv3 library might be.   What are the differences between GNU LGPL v2.1 and GNU LGPL v3?In particular, I know that regular GPLv3 has many anti-drm and anti-patent clauses.  In principal I don't have anything against these clauses, but I will these suddenly apply to the main application if I choose to use an LGPLv3 library.The rules of LGPL v2.1 seems to only apply to the library that you use or modify. It says nothing about the main application. (Assuming no static linking etc.)Thus, in the niche-market software provider where I work, we regularly use (and contribute to) LGPL licensed libraries, without needing to open-source our main application.Does this change in LGPLv3?The question https://stackoverflow.com/questions/1108238/differences-between-gnu-lgpl-v2-1-and-gnu-lgpl-v3 got a couple of answers, but none that address any new obligations that the main application might have.To clarify:  I'm asking about the LGPL v3, not plain GPLv3. Do any of the Tivoization / patent grant requirements bleed through from an LGPLv3 library to the host application? 
Downsides of GNU LGPL v3 vs. GNU LGPL v2.1?
open source;licensing;lgpl