I know that software licensing is an eternal issue (at least until property of ideas is (eventually) abolished). I have been studying copyright law and related stuff for some time.
I know that changing the license used depends on tracking people that contributed to the codebase and that is a very hard task on large projects. Especially when people come and go and then get impossible to be contacted.
That is why I would like to make a public statement here making it clear that I allow the use of later versions of the GPL on any code licensed under GPLv2 that I have ever contributed to Inkscape in the past. On new code I plan to say it explicitly on the headers of sourcecode files.
Of course, the effective switch to "GPLv3 or later" versions of the license will depend on others also making this public statement. So I encourage other developers to make it in the hope that we could eventually switch the project to "GPLv3 or later".
I know it is difficult to achieve, but I am trying to make the first step. Those who agree, please say so.
Felipe C. da S. Sanches (JucaBlues)