[libvirt] Drop support for old libvirt versions?

A while ago, we agreed to drop support for QEMU versions older than 0.12.0, with the rationale that we should focus on operating systems that are still supported by the respective vendors, eg. RHEL/CentOS 6, Ubuntu 12.04 and SLES 11. Recently, when discussing how to ensure a certain change will not break migration with libvirt <= 0.9.4, I started wondering whether we should apply the same rationale to libvirt versions as well. Here's a quick run down of relevant libvirt versions:   SLES 11        → ???   RHEL 6.0       → 0.8.1   Ubuntu 12.04   → 0.9.2   RHEL 6.8       → 0.10.2   Ubuntu 12.04.5 → 0.9.8   SLES 11 SP4    → 1.2.5 One thing I'm not clear about is whether or not SUSE, Red Hat and Canonical will support old minor releases or just the latest one. If the latter, we could safely drop support for anything older than 0.9.8, which incidentally would make the discussion referenced above entirely moot ;) In any case, having a well-defined cut-off point has been very useful when dealing with QEMU, so I think having one for libvirt itself would be beneficial too. Looking forward to your thoughts on this :) --  Andrea Bolognani / Red Hat / Virtualization