Please report only issues/bugs which are new in the prerelease.   We've been holding back on this release a few days waiting for updated Intel ixgbe (10Gbit) OOT driver which builds correctly with 4.18 kernel.  But no update yet so this release uses 4.17.19 kernel.   Every major subsystem has been updated.  In addition @bonienl has added some really cool features and update the default themes to match our new branding.   Release notes: Version 6.6.0-rc1 2018-08