Mirage 4.11.0 released! With built-in support for µTCP, and DNS/log/everything configuration via DHCP

[Hannes Mehnert <hannes@xxxxxxxxxxx>]

Dear MirageOS hackers,

after the longer 4.10 line of mirage, we just released mirage 4.11.0.

To summarize the changes within the last year (4.10 released September 
2025):
- µTCP can be used when `--utcp` is provided at configuration time (per 
network device, i.e. --utcp, --management-utcp, --private-utcp) 
https://github.com/mirage/mirage/pull/1636
- DHCP is now enabled by default, and is able to set the DNS server in 
the DNS stack (and of course other DHCP configuration options, not only 
IP address and routers) https://github.com/mirage/mirage/pull/1628
- each unikernel accepts a `--name` argument (available via 
Mirage_runtime.name ()) https://github.com/mirage/mirage/pull/1611; this 
is sent as requested Hostname in DHCP 
https://github.com/mirage/mirage/pull/1632
- unikraft target https://github.com/mirage/mirage/pull/1607
- there's a ~local_libs argument to Mirage.main to use local dune libs 
(https://github.com/mirage/mirage/pull/1609, see mirage-skeleton example 
https://github.com/mirage/mirage-skeleton/tree/main/tutorial/local-library)
- Makefile now includes the output file extensions 
https://github.com/mirage/mirage/pull/1619
- breaking: --dhcp=true/false is now a flag --no-dhcp 
https://github.com/mirage/mirage/pull/1636
- ?tcp, ?dhcp_key, ?net_key have been removed from Mirage.*stack* 
https://github.com/mirage/mirage/pull/1636
- boot arguments use "-" instead of "_" (i.e. "--dns-servers") 
https://github.com/mirage/mirage/pull/1638
- various cleanups and fixes https://github.com/mirage/mirage/pull/1612, 
https://github.com/mirage/mirage/pull/1615, 
https://github.com/mirage/mirage/pull/1614, 
https://github.com/mirage/mirage/pull/1613, 
https://github.com/mirage/mirage/pull/1620, 
https://github.com/mirage/mirage/pull/1622, 
https://github.com/mirage/mirage/pull/1623, 
https://github.com/mirage/mirage/pull/1625, 
https://github.com/mirage/mirage/pull/1628, 
https://github.com/mirage/mirage/pull/1635
There may be some further things that broke. Please let us know if 
you're stuck upgrading your unikernel.
## µTCP

µTCP (https://github.com/robur-coop/utcp) is a TCP stack developed from 
scratch based on the HOL4 model 
(https://www.cl.cam.ac.uk/~pes20/Netsem/). The stack is purely in OCaml 
and value-passing style (sans-IO, as pioneered by OCaml-TLS [David 
Kaloper Meršinjak]). Already now we have another backend for µTCP that 
doesn't rely on lwt - something very hard to do with the existing "old" 
TCP stack from https://github.com/mirage/mirage-tcpip (src/tcp).
There is still ongoing work on µTCP, but we are also testing it since 
more than a year on some production systems on the Internet with good 
results. It is smaller, allocates less, and (hopefully) easier to 
maintain than the old TCP stack.
## DHCP

For deployments, we now fully support DHCP, such that configuration 
parameters (syslog sink, metrics, DNS server, ...) can be taken from 
DHCP. This required some restructuring of the DHCP stack, as well as 
some work on the mirage tool to provide DHCP configuration information 
to other subsystems (without them having to depend on the DHCP package).

If you're interested in further details, don't hesitate to reach out via 
mail (on this list, or privately). We're in full momentum re-deploying 
our unikernel hive, removing the plasters we needed before we had these 
opportunities.

Happy victory day (bomber harris do it again),

Hannes