Heads up, Debian IKE/IPsec users.

Starting with strongSwan 6.1.0-1 (currently in Debian unstable and targeted at Debian 14 Forky), the IKEv1 protocol has been disabled. This is aligned with upstream decision. Considering IKEv2 is already nearly old enough to drink in the USA (RFC 4306 will turn 21 next December) and IKEv1 has weaknesses, the disabling is long overdue amd will permit upstream to remove some code in the upcoming years.

At this point there is no good reason not to migrate to IKEv2 and exposing IKEv1 code in all Debian installation is no longer relevant. All IKEv1 users using Debian 13 Trixie (either site to site, gateway or roadwarrior client) should investigate IKEv2 protocol (or other options).

Note that some plugins have also been disabled upstream for security/maintenance reasons and we followed suite in Debian. The Debian relevant ones are: af-alg, led, padlock.