A number of bug fixes and security fixes have been backported for this release to include the features available in Xen 4.4, Xen 4.5 and Xen 4.6.

A fix was applied to improve the code that handled cycling through the E820 map sent to the bootloader by the BIOS during boot. This fix resolved a potential mismatch error that resulted in a Dom0 kernel crash during boot on some systems.

A new feature allowing the dynamic configuration of VBD (Virtual Block Device) I/O buffers has been applied to allow for better performance tuning per virtual block device, depending on specific application requirements. The values for these buffer configuration settings are available in /sys/devices/vbd-xxx/max_indirect_segs, /sys/devices/vbd-xxx/max_ring_page_order and /sys/devices/vbd-xxx/max_queues.