No
GNU General Public License v3.0 is strong copyleft; combining it into a GNU Lesser GPL v2.1 project would force the combined work to be GNU General Public License v3.0 (not GNU Lesser GPL v2.1). If your project must remain GNU Lesser GPL v2.1, avoid GNU General Public License v3.0 code.
| License | Family | Patent grant |
|---|---|---|
| GNU General Public License v3.0 (GPL-3.0) | strong-copyleft | Yes |
| GNU Lesser GPL v2.1 (LGPL-2.1) | weak-copyleft | No (implicit at most) |
GNU General Public License v3.0: GPLv3 adds explicit patent grant + anti-tivoisation; updated copyleft language.
GNU Lesser GPL v2.1: Library copyleft: dynamic linking permitted from non-LGPL code without triggering full copyleft.
If you found this page because you're trying to figure out whether shipping a particular dependency is safe, the answer above is a starting point — not a substitute for reading the actual licenses or talking to a lawyer when stakes are high.
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