Hello everyone,
tl;dr: Most Inkscape code is GPLv2+, but the complete program is GPLv3+ due to bits of code from GIMP.
The Inkscape Board has resolved some licensing problems within our codebase and Inkscape is now available under GPL version 3 or later.
The vast majority of code in Inkscape is covered by GPL version 2 or later; the authors of 4 files that were GPL v2 only were contacted and all agreed to relicense their contributions to GPL v2+, while one file was rewritten from scratch. However, Inkscape also includes a few files from GIMP, which are available under GPL v3+ only. Therefore, redistribution of the complete program is currently possible only under the terms of GPL version 3 or later. We would like to keep existing source and new contributions GPL v2+, so that we may make Inkscape available under GPL v2+ if the GIMP code is removed.
Best regards, Krzysztof