DokuWiki currently embeds SimplePie version 1.0.1, which is quite outdated. The latest available version is 1.2, and it would be nice to update to it. This is not straightforward, though, as SimplePie_File API seems to have changed in an incompatible way: a simple library replacement does not work at all.
This is important for the Debian distribution, as the Debian policy requires programs to use shared libraries instead of embedded ones, for space and security reasons. And, in Debian, the shared SimplePie library is 1.2, not the old 1.0.1… :-)
For the record, I spotted this with the Debian bug report http://bugs.debian.org/603390