Welcome Lenny
Just did an aptitude dist-upgrade to get planet.classpath.org and the main IcedTea backup server from Debian Etch to Debian Lenny. Pretty smooth.
Needed to adjust some apache2 NameVirtualHost settings as outlined in the release notes. And sadly, had to pin mercurial to 0.9.5, since newer versions don’t work nicely with the forest extension and serving hg through http hgwebdir. But that was it. Everything else went without any hiccups.
But if you use one of those servers and do notice something wrong, please let me know.