Interest in DTLS 1.3 support?
OpenSSL has a [DTLS 1.3 feature branch](https://github.com/openssl/openssl/tree/feature/dtls-1.3) currently only [tended to by a single contributor as time permits](https://github.com/openssl/openssl/issues/13900#issuecomment-3306151646). At the same time, the somewhat similar QUIC protocol has been made available in master and seems to have full support by the community.
This discussion is to solicit both technical and business input from any community as to whether
there is wider (any?) interest in DTLS 1.3, both from a usage perspective as well as a contribution perspective;
any release should be targeted for such effort;
more forums than this should receive this question to get representative feedback.

Paul Yang Wed 1 Oct 2025 7:57AM
@Tomas Mraz If the fund is kind of limited and as per we have the consensus that OpenSSL would be more used at server side, then how about the Foundation start from the DTLS-server stuff?

Tomas Mraz Wed 1 Oct 2025 8:24AM
@Paul Yang I don't really think this will make the work smaller and we need both sides for testing.
Frederik Wedel-Heinen Wed 24 Sep 2025 3:52PM
As mentioned in the GitHub issue thread: my company is interested in the feature to enable pqc for encrypted voice and video calls.
I can contribute code and reviews. But it will be in my free time.

Ryan Hooper Wed 24 Sep 2025 6:38PM
I know Cisco is interested in having this feature. I am willing to help in this area the best that I can.
Alicja Kario Thu 25 Sep 2025 11:37AM
DTLS 1.3 is the only way to have PQC in DTLS, so I'd say it is quite important...
Michael Baentsch Mon 29 Sep 2025 7:41AM
This is true -- but then begs the question: How much usage of DTLS (via OpenSSL) is there already? Could we try to convince that (DTLS 1.2) community to contribute more to 1.3 (and if only to close the PQC gap there)? Does anyone know of "heavy OpenSSL DTLS (1.2)" users?

Craig Lorentzen Thu 25 Sep 2025 4:26PM
+1 for DTLS 1.3 as an important feature if only for PQC availability
Michael Baentsch Mon 29 Sep 2025 7:48AM
Thanks everyone for their statements of interest -- particularly for possible contributions! (Hopefully :) last question from my side: Is the (pretty long) discussion in GH (https://github.com/openssl/openssl/issues/13900 sufficiently well-structured to allow interested contributors to pick up tasks or should there be more "bite sized" tasks, e.g., separate issues? Would there be interest for a kind-of "birds of a feather" session at the OpenSSL conference around how to speed up DTLS development?
Frederik Wedel-Heinen Mon 29 Sep 2025 10:37AM
A session would be a great place to start. And we could post a summary to the GitHub issue to distribute the knowledge to a wider audience.
Michael Baentsch Wed 1 Oct 2025 6:14AM
@Hana Andersen I know you have too much to do already these days, but allow me to bring the above to your attention anyway with the question whether this can still be facilitated somehow? Alternatively the question to @Jon Ericson : Would you be willing to at least "pick up" this topic somehow in your "community talks" at the conference such as to somehow physically bring together people interested in this topic also attending the conference? Even a quick informal personal get-together might do a lot to move this forward.

Jon Ericson Thu 2 Oct 2025 8:09AM
@baentsch I don't know if there is a formal way to do this at the conference, but I will ask around to see if we can make something happen.

Jon Ericson Tue 7 Oct 2025 5:35AM
I've booked the London room (using https://openssl-conference.org/meetingrooms/reservation/) for today at 12 to 1 pm. I also sent out an invite to the people I believe are at the conference. Please add other people to the invite if I missed anyone.
If the time doesn't work for you (it is designated for lunch) please suggest another time on the invite. Scheduling is always awkward, but at least this time we don't need to worry about timezones!

Jon Ericson Tue 7 Oct 2025 12:06PM
I updated the invite for tomorrow at noon. Sorry for the late notice this morning.

Jon Ericson Wed 8 Oct 2025 5:02AM
Turns out the meeting happened and there will be a writeup soon.
Michael Baentsch Wed 8 Oct 2025 5:23AM
Thanks @Jon Ericson for sending the invite around. Thanks @Frederik Wedel-Heinen @Ryan Hooper @Jeff Johnson for coming to the meeting.
My take: This feature is very much desired by Cisco and the whole team (Ryan in the lead) is very much motivated to put in work to fix the remaining issues by adding tests and required code to get this "across the finishing line". Frederik stated his personal change of priorities to other things but confirmed his willingness to still serve as reviewer (and possible "code guide" if needed) for anything Ryan does. I'm myself willing to help with anything around PQC (although assuming things should work smoothly as testing had been done earlier using oqsprovider). Jeff stated management support by Cisco to move this forward.
This, together with @Tomas Mraz statement above to help with reviews as and when PRs become available to me seems like there is a plan and commitment to move forward. It would be nice if someone now could post/agree a timeline (deadline) by which this work should be completed to give this the "final push" and urgency. @Matt Caswell : Would you think 4.0 is a realistic goal and would you support (Ryan working for the Foundation on) that?
PS: Anyone violently disagreeing with this summary, please speak up and correct me (and/or hit me over the head while we're all in the same place :-)

Tomas Mraz Wed 8 Oct 2025 4:22PM
@Michael Baentsch I think 4.0 is possible goal, although that will require a concerted effort. However at worst this will be finished for 4.1.

Matt Caswell Fri 10 Oct 2025 10:16AM
4.0 seems like a very reasonable objective.
Frederik Wedel-Heinen Tue 14 Oct 2025 9:07AM
I did a summary of the DTLS feature branch status on the issue page:
https://github.com/openssl/openssl/issues/13900#issuecomment-3400806024
@Ryan Hooper Please let me know if you need a teams meeting to resolve the questions you might have. And please do ping me for reviews.

Aditya Koranga Tue 14 Oct 2025 1:46PM
@Frederik Wedel-Heinen Thanks for the summary.
Michael Baentsch · Mon 29 Sep 2025 7:41AM
That's excellent news closing an important gap (timely and thorough reviews). Thanks for sharing this information @Tomas Mraz !