License question

Good Morning,

I’ve a question about the license of Spark.

I’ve created a branded version with some new features for my company, and we’re planning to distribute that branded version to our clients and our suppliers, only. I’ve checked the LGPL license, but the information available about it it’s not very clear.

I would like to know if is it possible to distribute it without the source-code attached to it.

I believe you need to include the source, since you are distributing the app.

I’m not 100% sure of that because of this:

The GNU Project has two principal licenses to use for libraries. One is the GNU Lesser GPL; the other is the ordinary GNU GPL. The choice of license makes a big difference: using the Lesser GPL permits use of the library in proprietary programs; using the ordinary GPL for a library makes it available only for free programs…

In my understanding, proprietary programs are the ones which are closed-source.