diff --git a/pkgs/servers/sql/postgresql/ext/tds_fdw.nix b/pkgs/servers/sql/postgresql/ext/tds_fdw.nix
index 19331f350c55..49c3ee044b2b 100644
--- a/pkgs/servers/sql/postgresql/ext/tds_fdw.nix
+++ b/pkgs/servers/sql/postgresql/ext/tds_fdw.nix
@@ -2,21 +2,23 @@
 
 stdenv.mkDerivation rec {
   pname = "tds_fdw";
-  version = "2.0.2";
+  # Move to stable version when it's released.
+  version = "unstable-2021-12-14";
 
   buildInputs = [ postgresql freetds ];
 
   src = fetchFromGitHub {
     owner  = "tds-fdw";
     repo   =  pname;
-    rev    = "refs/tags/v${version}";
-    sha256 = "024syj21gmdfkpr51l8ca70n5jimr35zwdy719b8h4zjn64ci1fk";
+    rev    = "1611a2805f85d84f463ae50c4e0765cb9bed72dc";
+    sha256 = "sha256-SYHo/o9fJjB1yzN4vLJB0RrF3HEJ4MzmEO44/Jih/20=";
   };
 
   installPhase = ''
-    install -D tds_fdw.so                  -t $out/lib
-    install -D sql/tds_fdw--${version}.sql -t $out/share/postgresql/extension
-    install -D tds_fdw.control             -t $out/share/postgresql/extension
+    version="$(sed -En "s,^default_version *= *'([^']*)'.*,\1,p" tds_fdw.control)"
+    install -D tds_fdw.so      -t $out/lib
+    install -D sql/tds_fdw.sql    "$out/share/postgresql/extension/tds_fdw--$version.sql"
+    install -D tds_fdw.control -t $out/share/postgresql/extension
   '';
 
   meta = with lib; {
@@ -25,6 +27,5 @@ stdenv.mkDerivation rec {
     maintainers = [ maintainers.steve-chavez ];
     platforms   = postgresql.meta.platforms;
     license     = licenses.postgresql;
-    broken = versionAtLeast postgresql.version "11.0";
   };
 }