I deployed a Java Web Start application using the JWS Version Download Protocol as outlined on Avoiding Unnecessary Update Checks.
According to this manual, JWS should check in the background if the version number has changed and download the new app if necessary. But it does not work for me - a check of my server logfiles shows that JWS doesn't even connect to the server, so the client will never know that there is a newer version available.
This is the main JNLP file:
<?xml version="1.0" encoding="utf-8"?>
<!-- JNLP File for PEE Mail Client -->
<jnlp spec="1.0+" codebase="http://www.peemail.org/home/projects/pee/beta/" >
<!-- information -->
<information>
<title>PEE Mail</title>
<vendor>Andreas Junius, Software Engineer</vendor>
<homepage href="http://www.peemail.org/" />
<description>PEE - Privacy Enhanced Email</description>
<icon kind="shortcut" href="stamp16x16.png" width="16" height="16" />
<icon kind="default" href="stamp32x32.png" width="32" height="32" />
<icon kind="shortcut" href="stamp32x32.png" width="32" height="32" />
<icon kind="splash" href="javanerd_500x290.png" width="500"
height="290" />
<shortcut online="true" install="true">
<desktop />
<menu submenu="Javanerd" />
</shortcut>
<offline-allowed />
</information>
<!-- full access required -->
<security>
<all-permissions />
</security>
<!-- check always for updates -->
<update check="background" policy="always" />
<!-- resources -->
<resources>
<j2se version="1.8+" />
<jar href="peemail.jar" main="true" download="eager" size="1143096" version="01.00.66" />
<property name="jnlp.versionEnabled" value="true"/>
<!-- cryptographic libraries -->
<extension name="BouncyCastle cryptography library" href="bcprov.jnlp" />
<extension name="BouncyCastle pkix library" href="bcpkix.jnlp" />
</resources>
<!-- main class -->
<application-desc main-class="org.peemail.client.swing.PeeMain" />
</jnlp>
What did I miss?