diff --git a/pkgs/applications/networking/mailreaders/notmuch/muchsync.nix b/pkgs/applications/networking/mailreaders/notmuch/muchsync.nix
index 61cae422b3a3..a0f362d6c493 100644
--- a/pkgs/applications/networking/mailreaders/notmuch/muchsync.nix
+++ b/pkgs/applications/networking/mailreaders/notmuch/muchsync.nix
@@ -16,7 +16,7 @@ stdenv.mkDerivation rec {
     inherit version;
   };
   src = fetchurl {
-    url = "http://www.muchsync.org/src/${pname}-${version}.tar.gz";
+    url = "https://www.muchsync.org/src/${pname}-${version}.tar.gz";
     hash = "sha256-+D4vb80O9IE0df3cjTkoVoZlTaX0FWWh6ams14Gjvqw=";
   };
   nativeBuildInputs = [ pkg-config ];