diff --git a/.ci/scripts/checkout_complement.sh b/.ci/scripts/checkout_complement.sh
index 379f5d4387..7730d8a4b1 100755
--- a/.ci/scripts/checkout_complement.sh
+++ b/.ci/scripts/checkout_complement.sh
@@ -21,5 +21,5 @@ for BRANCH_NAME in "$GITHUB_HEAD_REF" "$GITHUB_BASE_REF" "${GITHUB_REF#refs/head
     continue
   fi
 
-  (wget -O - "https://github.com/matrix-org/complement/archive/$BRANCH_NAME.tar.gz" | tar -xz --strip-components=1 -C complement) && break
+  (wget -O - "https://github.com/famedly/complement/archive/$BRANCH_NAME.tar.gz" | tar -xz --strip-components=1 -C complement) && break
 done
diff --git a/.github/workflows/famedly-tests.yml b/.github/workflows/famedly-tests.yml
index a328a6f4f6..fac74cdd6d 100644
--- a/.github/workflows/famedly-tests.yml
+++ b/.github/workflows/famedly-tests.yml
@@ -25,7 +25,7 @@ jobs:
       - uses: Swatinem/rust-cache@68b3cb7503c78e67dae8373749990a220eb65352
       - uses: matrix-org/setup-python-poetry@v2
         with:
-          python-version: "3.x"
+          python-version: "3.13"
           poetry-version: "2.1.1"
           extras: "all"
       - run: poetry run scripts-dev/generate_sample_config.sh --check
@@ -49,7 +49,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
-          python-version: "3.x"
+          python-version: "3.13"
       - run: .ci/scripts/check_lockfile.py
 
   lint:
@@ -63,6 +63,7 @@ jobs:
         uses: matrix-org/setup-python-poetry@v2
         with:
           poetry-version: "2.1.1"
+          python-version: "3.13"
           install-project: "false"
 
       - name: Run ruff check
@@ -91,6 +92,7 @@ jobs:
           # https://github.com/matrix-org/synapse/pull/15376#issuecomment-1498983775
           # To make CI green, err towards caution and install the project.
           install-project: "true"
+          python-version: "3.13"
           poetry-version: "2.1.1"
 
       # Cribbed from
@@ -124,6 +126,7 @@ jobs:
       - uses: matrix-org/setup-python-poetry@v2
         with:
           poetry-version: "2.1.1"
+          python-version: "3.13"
           extras: "all"
       - run: poetry run scripts-dev/check_pydantic_models.py
 
@@ -161,7 +164,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
-          python-version: "3.x"
+          python-version: "3.13"
       - run: "pip install rstcheck"
       - run: "rstcheck --report-level=WARNING README.rst"
 
diff --git a/docker/complement/conf/workers-shared-extra.yaml.j2 b/docker/complement/conf/workers-shared-extra.yaml.j2
index 48b44ddf90..b55eed4040 100644
--- a/docker/complement/conf/workers-shared-extra.yaml.j2
+++ b/docker/complement/conf/workers-shared-extra.yaml.j2
@@ -129,6 +129,8 @@ experimental_features:
   msc3984_appservice_key_query: true
   # Invite filtering
   msc4155_enabled: true
+  # Media Attachment
+  msc3911_enabled: true
 
 server_notices:
   system_mxid_localpart: _server
diff --git a/docker/configure_workers_and_start.py b/docker/configure_workers_and_start.py
index 6f25653bb7..fbe4dc14e2 100755
--- a/docker/configure_workers_and_start.py
+++ b/docker/configure_workers_and_start.py
@@ -117,7 +117,7 @@
     },
     "media_repository": {
         "app": "synapse.app.generic_worker",
-        "listener_resources": ["media", "client"],
+        "listener_resources": ["media", "client", "replication"],
         "endpoint_patterns": [
             "^/_matrix/media/",
             "^/_synapse/admin/v1/purge_media_cache$",
@@ -125,7 +125,7 @@
             "^/_synapse/admin/v1/user/.*/media.*$",
             "^/_synapse/admin/v1/media/.*$",
             "^/_synapse/admin/v1/quarantine_media/.*$",
-            "^/_matrix/client/v1/media/.*$",
+            "^/_matrix/client/(v1|unstable/.*)/media/.*$",
             "^/_matrix/federation/v1/media/.*$",
         ],
         # The first configured media worker will run the media background jobs
@@ -448,6 +448,9 @@ def add_worker_roles_to_shared_config(
     if "federation_sender" in worker_types_set:
         shared_config.setdefault("federation_sender_instances", []).append(worker_name)
 
+    if "media_repository" in worker_types_set:
+        shared_config.setdefault("media_repo_instances", []).append(worker_name)
+
     # Update the list of stream writers. It's convenient that the name of the worker
     # type is the same as the stream to write. Iterate over the whole list in case there
     # is more than one.
@@ -468,6 +471,17 @@ def add_worker_roles_to_shared_config(
                     "host": "localhost",
                     "port": worker_port,
                 }
+        if worker == "media_repository":
+            # Just like for stream_writers, media workers now need to be on the instance_map
+            if os.environ.get("SYNAPSE_USE_UNIX_SOCKET", False):
+                instance_map[worker_name] = {
+                    "path": f"/run/worker.{worker_port}",
+                }
+            else:
+                instance_map[worker_name] = {
+                    "host": "localhost",
+                    "port": worker_port,
+                }
 
 
 def merge_worker_template_configs(
diff --git a/scripts-dev/complement.sh b/scripts-dev/complement.sh
index 08b500ecd6..07ad04423d 100755
--- a/scripts-dev/complement.sh
+++ b/scripts-dev/complement.sh
@@ -230,6 +230,7 @@ test_packages=(
     ./tests/msc3967
     ./tests/msc4140
     ./tests/msc4155
+    ./tests/msc3911
 )
 
 # Enable dirty runs, so tests will reuse the same container where possible.