two related problems.
1.) When Java Web Start downloads and installs a later version of the jre, and then launches the current application with the new jre, it still uses (what was the latest before the auto dl) the older version of java web start to launch the app.
2.) if the specification version in a jnlp file is set to later than the curently installed java web start can handel, java web start will exit with an error, instead of downloading the latest java web start and using it (if that version can handle the given specification version).