diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d9aedddb9..23d197fa3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -367,7 +367,7 @@ jobs:
       # run sliding sync and point it at the postgres container and synapse container.
       # the postgres container needs to be above this to make sure it has started prior to this service.
       slidingsync:
-        image: "ghcr.io/matrix-org/sliding-sync:v0.99.2"
+        image: "ghcr.io/matrix-org/sliding-sync:v0.99.11" # keep in sync with ./coverage.yml
         env:
           SYNCV3_SERVER: "http://synapse:8008"
           SYNCV3_SECRET: "SUPER_CI_SECRET"
@@ -378,9 +378,7 @@ jobs:
       # tests need a synapse: this is a service and not michaelkaye/setup-matrix-synapse@main as the
       # latter does not provide networking for services to communicate with it.
       synapse:
-        # Custom image built from https://github.com/matrix-org/synapse/tree/v1.72.0/docker/complement
-        # with a dummy /complement/ca set
-        image: ghcr.io/matrix-org/synapse-service:v1.72.0
+        image: ghcr.io/matrix-org/synapse-service:v1.72.0 # keep in sync with ./coverage.yml
         env:
             SYNAPSE_COMPLEMENT_DATABASE: sqlite
             SERVER_NAME: synapse
diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index 60c03364f..5ee5a9e2c 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -48,7 +48,7 @@ jobs:
       # run sliding sync and point it at the postgres container and synapse container.
       # the postgres container needs to be above this to make sure it has started prior to this service.
       slidingsync:
-        image: "ghcr.io/matrix-org/sliding-sync:v0.99.11"
+        image: "ghcr.io/matrix-org/sliding-sync:v0.99.11" # keep in sync with ./ci.yml
         env:
           SYNCV3_SERVER: "http://synapse:8008"
           SYNCV3_SECRET: "SUPER_CI_SECRET"
@@ -59,9 +59,7 @@ jobs:
       # tests need a synapse: this is a service and not michaelkaye/setup-matrix-synapse@main as the
       # latter does not provide networking for services to communicate with it.
       synapse:
-        # Custom image built from https://github.com/matrix-org/synapse/tree/v1.72.0/docker/complement
-        # with a dummy /complement/ca set
-        image: ghcr.io/matrix-org/synapse-service:v1.72.0
+        image: ghcr.io/matrix-org/synapse-service:v1.72.0 # keep in sync with ./ci.yml
         env:
             SYNAPSE_COMPLEMENT_DATABASE: sqlite
             SERVER_NAME: synapse
diff --git a/testing/matrix-sdk-integration-testing/assets/docker-compose.yml b/testing/matrix-sdk-integration-testing/assets/docker-compose.yml
index 2c8f6354f..81a630ace 100644
--- a/testing/matrix-sdk-integration-testing/assets/docker-compose.yml
+++ b/testing/matrix-sdk-integration-testing/assets/docker-compose.yml
@@ -27,7 +27,7 @@ services:
       - ./data/db:/var/lib/postgresql/data
 
   sliding-sync-proxy:
-    image: ghcr.io/matrix-org/sliding-sync:v0.99.4
+    image: ghcr.io/matrix-org/sliding-sync:v0.99.11
     depends_on:
       postgres:
         condition: service_healthy