diff --git a/hosts/hainich/services/mattermost.nix b/hosts/hainich/services/mattermost.nix
index 117c667..9271836 100644
--- a/hosts/hainich/services/mattermost.nix
+++ b/hosts/hainich/services/mattermost.nix
@@ -159,6 +159,9 @@
           ClusterSettings.Enable = false;
           MetricsSettings.Enable = false;
           GuestAccountsSettings.Enable = false;
+          # this is just the general allow-this-at-all switch; users
+          # still have to turn it on for themselves
+          FeatureFlags.CollapsedThreads = true;
         };
 
         # turn of the weirder parts of this module (which insist on passwords
diff --git a/nix/sources.json b/nix/sources.json
index 7ff1634..9627e63 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -18,24 +18,23 @@
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "mattermost-server": {
-        "branch": "release-5.31",
         "description": "Open source Slack-alternative in Golang and React - Mattermost",
         "homepage": "https://mattermost.com",
         "owner": "mattermost",
         "repo": "mattermost-server",
-        "rev": "facf75eaecfa62446ba36889c26c1cb852ffff46",
-        "sha256": "0rp0pq93k6rsf7jhab3lk1bn9ma9pml36hp5wfsmm3qlj3szr8md",
+        "rev": "f46b068ecf3b20a0d6e529618813e0ef6b85ed72",
+        "sha256": "1w994j2ckv82h53c7f5mzh7mq2l1jnhx68vmx6sydz8mc8yd4gpa",
         "type": "tarball",
-        "url": "https://github.com/mattermost/mattermost-server/archive/facf75eaecfa62446ba36889c26c1cb852ffff46.tar.gz",
+        "url": "https://github.com/mattermost/mattermost-server/archive/f46b068ecf3b20a0d6e529618813e0ef6b85ed72.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
-        "version": "5.34.3"
+        "version": "5.37.0"
     },
     "mattermost-webapp": {
-        "sha256": "0c1q4s8w7q26xb387k1660fa6prb4n1b06csx90bb206y98ax6hc",
+        "sha256": "0na9drwnsr5fbrv6qq38dgvd0laj3wjs734ik5s673c0azqlm4kn",
         "type": "tarball",
-        "url": "https://releases.mattermost.com/5.34.3/mattermost-5.34.3-linux-amd64.tar.gz",
+        "url": "https://releases.mattermost.com/5.37.0/mattermost-5.37.0-linux-amd64.tar.gz",
         "url_template": "https://releases.mattermost.com/<version>/mattermost-<version>-linux-amd64.tar.gz",
-        "version": "5.34.3"
+        "version": "5.37.0"
     },
     "mumble-website": {
         "branch": "master",