diff -Nru ubiquity-24.04.4/debian/changelog ubiquity-24.04.5/debian/changelog
--- ubiquity-24.04.4/debian/changelog	2024-04-09 00:00:03.000000000 +0000
+++ ubiquity-24.04.5/debian/changelog	2024-04-14 18:21:18.000000000 +0000
@@ -1,3 +1,10 @@
+ubiquity (24.04.5) noble; urgency=medium
+
+  [ Dave Jones ]
+  * plugins/ubi-timezone.py: Update to support libsoup3 API (LP: #1987454)
+
+ -- Steve Langasek <steve.langasek@ubuntu.com>  Sun, 14 Apr 2024 11:21:18 -0700
+
 ubiquity (24.04.4) noble; urgency=medium
 
   * Bump webkit gir dependency to 4.1.
diff -Nru ubiquity-24.04.4/ubiquity/frontend/gtk_ui.py ubiquity-24.04.5/ubiquity/frontend/gtk_ui.py
--- ubiquity-24.04.4/ubiquity/frontend/gtk_ui.py	2023-09-28 21:43:01.000000000 +0000
+++ ubiquity-24.04.5/ubiquity/frontend/gtk_ui.py	2024-04-14 18:18:16.000000000 +0000
@@ -963,7 +963,7 @@
         return True
 
     def on_slideshow_link_clicked(self, web_view, decision, decision_type):
-        gi.require_version('WebKit2', '4.0')
+        gi.require_version('WebKit2', '4.1')
         from gi.repository import WebKit2
         if decision_type == WebKit2.PolicyDecisionType.NEW_WINDOW_ACTION:
             request = decision.get_request()
@@ -1000,7 +1000,7 @@
 
         slides = 'file://%s#%s' % (slideshow_main, parameters_encoded)
 
-        gi.require_version('WebKit2', '4.0')
+        gi.require_version('WebKit2', '4.1')
         from gi.repository import WebKit2
         # We have no significant browsing interface, so there isn't much point
         # in WebKit creating a memory-hungry cache.
diff -Nru ubiquity-24.04.4/ubiquity/plugins/ubi-timezone.py ubiquity-24.04.5/ubiquity/plugins/ubi-timezone.py
--- ubiquity-24.04.4/ubiquity/plugins/ubi-timezone.py	2024-04-08 23:47:54.000000000 +0000
+++ ubiquity-24.04.5/ubiquity/plugins/ubi-timezone.py	2024-04-14 18:18:23.000000000 +0000
@@ -95,7 +95,7 @@
     def changed(self, entry):
         import gi
         gi.require_version('Soup', '3.0')
-        from gi.repository import Gtk, GObject, GLib, Soup
+        from gi.repository import Gtk, GObject, GLib, Gio, Soup
 
         text = misc.utf8(self.city_entry.get_text())
         if not text:
@@ -114,15 +114,17 @@
                 self.geoname_session = Soup.Session()
             url = _geoname_url % (quote(text), misc.get_release().version)
             message = Soup.Message.new('GET', url)
-            message.request_headers.append('User-agent', 'Ubiquity/1.0')
+            message.get_request_headers().replace('User-agent', 'Ubiquity/1.0')
             self.geoname_session.abort()
             if self.geoname_timeout_id is not None:
                 GLib.source_remove(self.geoname_timeout_id)
+            cancellable = Gio.Cancellable()
             self.geoname_timeout_id = \
                 GLib.timeout_add_seconds(2, self.geoname_timeout,
-                                         (text, model))
-            self.geoname_session.queue_message(message, self.geoname_cb,
-                                               (text, model))
+                                         (text, model, cancellable))
+            self.geoname_session.send_and_read_async(
+                message, GLib.PRIORITY_DEFAULT, cancellable, self.geoname_cb,
+                (text, model))
 
     def geoname_add_tzdb(self, text, model):
         if len(model):
@@ -147,16 +149,17 @@
                               str(loc.latitude), str(loc.longitude)])
 
     def geoname_timeout(self, user_data):
-        text, model = user_data
+        text, model, cancellable = user_data
+        cancellable.cancel()
         self.geoname_add_tzdb(text, model)
         self.geoname_timeout_id = None
         self.city_entry.get_completion().set_model(model)
         return False
 
-    def geoname_cb(self, session, message, user_data):
+    def geoname_cb(self, session, result, user_data):
         import syslog
         import json
-        from gi.repository import GLib, Soup
+        from gi.repository import GLib, Gio, Soup
 
         text, model = user_data
 
@@ -165,27 +168,37 @@
             self.geoname_timeout_id = None
         self.geoname_add_tzdb(text, model)
 
-        if message.status_code == Soup.KnownStatusCode.CANCELLED:
-            # Silently ignore cancellation.
-            pass
-        elif message.status_code != Soup.KnownStatusCode.OK:
-            # Log but otherwise ignore failures.
-            syslog.syslog(
-                'Geoname lookup for "%s" failed: %d %s' %
-                (text, message.status_code, message.reason_phrase))
+        message = session.get_async_result_message(result)
+        try:
+            response = session.send_and_read_finish(result)
+        except GLib.GError as err:
+            if err.code == Gio.IOErrorEnum.CANCELLED:
+                # Silently ignore cancellation.
+                pass
+            else:
+                # Log but otherwise ignore failures.
+                syslog.syslog(
+                    'Geoname lookup for "%s" failed: %s' % (text, err.message))
         else:
-            try:
-                for result in json.loads(message.response_body.data):
-                    model.append([
-                        result['name'], result['admin1'], result['country'],
-                        result['latitude'], result['longitude']])
-
-                # Only cache positive results.
-                self.geoname_cache[text] = model
-
-            except ValueError:
+            if message.get_status() != Soup.Status.OK:
+                # Log but otherwise ignore failures
                 syslog.syslog(
-                    'Server return does not appear to be valid JSON.')
+                    'Geoname lookup for "%s" failed: %s %s' %
+                    (text, message.get_status(), message.get_reason_phrase()))
+            else:
+                try:
+                    for result in json.loads(response.get_data().decode()):
+                        model.append([
+                            result['name'], result['admin1'],
+                            result['country'], result['latitude'],
+                            result['longitude']])
+
+                    # Only cache positive results.
+                    self.geoname_cache[text] = model
+
+                except ValueError:
+                    syslog.syslog(
+                        'Server return does not appear to be valid JSON.')
 
         self.city_entry.get_completion().set_model(model)