Version 2.0 of the KTX library has just been released.
Version 2 adds support for ETC2 and EAC textures and conversion of legacy LUMINANCE* and INTENSITY* formats when loading in an OpenGL core context. It includes KTX loader tests for OpenGL ES 3.0 and OpenGL 3.3. In addition a couple of nasty bugs have been fixed including one in the KTX writer where image rows were not padded to 4 bytes as required by the spec. Complete details of the changes can be found at http://www.khronos.org/opengles/sdk/tools/KTX/doc/libktx/history.html.
A new version of toktx has also been released. New features are ability to create KTX files with textures in sized internal formats and defaulting to RED and RG formats for 1 and 2 channel textures. Naturally it incorporates the bug-fixed writer from libktx.
Visit the KTX home page at http://www.khronos.org/opengles/sdk/tools/KTX/ to download these tools.