You might be reading this and about to flag it as a duplicate but wait. It’s different from the others. I am wondering if I can use QT, under the LGPL 2.1 license. For single client programs. The programs are only made for one company to use.
Will LPGL be ok?
The basic point of LGPL is that you can freely build anything on top of it as long as you are linking dynamically against the original binaries. Once you modify the library itself, you need to obey LGPL and distribute the code (but only for the library itself).
There are some distribution quirks, but invoking the library installation from your install program was OK.