diff --git a/flake.nix b/flake.nix
index 39183bfc..e8a53a96 100644
--- a/flake.nix
+++ b/flake.nix
@@ -41,6 +41,22 @@
         prometheus-exporter = ./config/extra/prometheus-exporter.nix;
       };
       overlays = {
+        matrixSynapseFix = final: prev: {
+          matrix-synapse-unwrapped = prev.matrix-synapse-unwrapped.overrideAttrs (finalAttrs: prevAttrs: rec {
+            version = "1.135.2";
+            src = prev.fetchFromGitHub {
+              owner = "element-hq";
+              repo = "synapse";
+              rev = "v${version}";
+              hash = "sha256-4HAA9Xq4C3DHxz0BgqBitfM4wZwPSEu+IO/OPfHzLVw=";
+            };
+            cargoDeps = final.rustPlatform.fetchCargoVendor {
+              inherit src;
+              hash = "sha256-4J92s6cSgsEIYQpbU6OOLI/USIJX2Gc7UdEHgWQgmXc=";
+            };
+            patches = [];
+          });
+        };
         librespotFixOverlay = final: prev: {
           librespot = (prev.librespot.override { withAvahi = true; }).overrideAttrs (finalAttrs: prevAttr: rec {
             # Build dev branch.
@@ -109,6 +125,7 @@
             sops-nix.nixosModules.sops
             self.nixosModules.prometheus-exporter
             ./config/hosts/matrix
+            { nixpkgs.overlays = [ self.overlays.matrixSynapseFix ]; }
           ];
         };