* New API action: SendCtrlAltDel, used to initiate a graceful shutdown,
if the guest has driver support for i8042 and AT Keyboard. See
[the docs](docs/api_requests/actions.md#sendctrlaltdel) for details.
* New metric counting the number of egress packets with a spoofed MAC:
`net.tx_spoofed_mac_count`.
* New API call: `PATCH /network-interfaces/`, used to update the rate limiters
on a network interface, after the start of a microVM.
Changed
* Added missing `vmm_version` field to the InstanceInfo API swagger
definition, and marked several other mandatory fields as such.
* New default command line for guest kernel:
`reboot=k panic=1 pci=off nomodules 8250.nr_uarts=0
i8042.noaux i8042.nomux i8042.nopnp i8042.dumbkbd`.
Fixed
* virtio-blk: VIRTIO_BLK_T_FLUSH now working as expected.
* Vsock devices can be attached when starting Firecracker using the jailer.
* Vsock devices work properly when seccomp filtering is enabled.