Disclaimer: I am not a lawyer.  Nothing I say is meant as legal advice.  Ask a lawyer if you need legal advice.  Et cetera, ad absurdum et ad nauseum.

Yes, figure out what they mean!  Again, you have been a one man project.  When others start to contribute, that makes one+.  I know a lot of people with small projects don't think much about these issues, but it does make sense even when starting out.  I'm planning on keeping my code separate for a while anyway.  You are in an enviable situation, Chris, no one ever WANTS to help me :)

Make sure you have a reason for switching GPL versions--there really can be a reason depending on your ethical position. Here is a handy compatibility chart:

​
​https://www.gnu.org/licenses/gpl-faq.html#AllCompatibility

I ​
tried reading
​the ​
GPL/LGPL 3
​ when I was thinking about converting​
, then pick
​ed​
up a phone to call a lawyer to see how much he would charge to read it back to me in English
​.  GPL 2.1 is much more readable, IMHO.  ​
​Furthermore, ​t
​​
his is part of the difference:

https://en.wikipedia.org/wiki/Tivoization
​

​Stallman has a point, but so does Torvalds.
​

​​
On Wed, Jun 24, 2015 at 4:33 AM, Christian Schafmeister <chris.schaf@verizon.net> wrote:
Up until now Clasp has been a one man (me) project.  I’ve borrowed a lot of code from Embedded Common Lisp (ECL) and it has an LGPL license so Clasp will keep the LGPL license although it may move to the 2.1 or 3.0 version of that license once I figure out what they mean.