Tim Bray has posted beta 6 of Genx, his pure C library for outputting canonical XML. This version fixes a bug that caused the code to break under some optimizers. This involves some changes to method signatures. Genx is published under the expat license. This is a very liberal, non-viral but GPL-compatible license.
Version 0.9.4 of TM4J, "a topic map processing engine written in Java providing a pure Java API, support for the Tolog query language, support for importing XTM and LTM syntaxes; support for exporting XTM syntax; persistence of topic map information in a wide variety of databases." THis release supports the TMAPI 1.0 beta.