diff --git a/changelog.d/19348.misc b/changelog.d/19348.misc
new file mode 100644
index 0000000000..d4255215d9
--- /dev/null
+++ b/changelog.d/19348.misc
@@ -0,0 +1 @@
+Drop support for Ubuntu 25.04 'Plucky Puffin', add support for Ubuntu 25.10 'Questing Quokka'.
\ No newline at end of file
diff --git a/docs/upgrade.md b/docs/upgrade.md
index 5e7fa31580..7c9efaccaf 100644
--- a/docs/upgrade.md
+++ b/docs/upgrade.md
@@ -117,6 +117,14 @@ each upgrade are complete before moving on to the next upgrade, to avoid
 stacking them up. You can monitor the currently running background updates with
 [the Admin API](usage/administration/admin_api/background_updates.html#status).
 
+# Upgrading to v1.146.0
+
+## Drop support for Ubuntu 25.04 Plucky Puffin, and add support for 25.10 Questing Quokka
+
+Ubuntu 25.04 Plucky Puffin [is end-of-life as of 17 Jan
+2026](https://endoflife.date/ubuntu). This release drops support for Ubuntu
+25.04, and in its place adds support for Ubuntu 25.10 Questing Quokka.
+
 # Upgrading to v1.144.0
 
 ## Worker support for unstable MSC4140 `/restart` endpoint
diff --git a/scripts-dev/build_debian_packages.py b/scripts-dev/build_debian_packages.py
index d462fe6c56..7741d4aecd 100755
--- a/scripts-dev/build_debian_packages.py
+++ b/scripts-dev/build_debian_packages.py
@@ -31,7 +31,7 @@ DISTS = (
     "debian:sid",  # (rolling distro, no EOL)
     "ubuntu:jammy",  # 22.04 LTS (EOL 2027-04) (our EOL forced by Python 3.10 is 2026-10-04)
     "ubuntu:noble",  # 24.04 LTS (EOL 2029-06)
-    "ubuntu:plucky",  # 25.04 (EOL 2026-01)
+    "ubuntu:questing",  # 25.10 (EOL 2026-07)
     "debian:trixie",  # (EOL not specified yet)
 )