-- sqlite >= 3.0 (default database)
-- mysql >= 5.1 (alternative to sqLite)
-- postgres >= 8.3 (alternative to sqLite)
+- sqlite >= 3.8 (default database, required)
+- mysql >= 5.1 (alternative to sqlite)
+- postgres >= 8.3 (alternative to sqlite)
+- libopus >= 0.9.14 (optional for experimental conversation tool)
+- libpulse >= 2.0 (optional for experimental conversation tool)
+- python-zbar >= 0.10 (optional for gnunet-qr)
+- TeX Live >= 2012 (optional for gnunet-bcd)