diff --git a/pkgs/applications/science/astronomy/gildas/default.nix b/pkgs/applications/science/astronomy/gildas/default.nix
index b716b0f2f90f..beb3bd92ea5e 100644
--- a/pkgs/applications/science/astronomy/gildas/default.nix
+++ b/pkgs/applications/science/astronomy/gildas/default.nix
@@ -7,8 +7,8 @@ let
 in
 
 stdenv.mkDerivation rec {
-  srcVersion = "sep20a";
-  version = "20200901_a";
+  srcVersion = "nov21a";
+  version = "20211101_a";
   pname = "gildas";
 
   src = fetchurl {
@@ -16,7 +16,7 @@ stdenv.mkDerivation rec {
     # source code of the previous release to a different directory
     urls = [ "http://www.iram.fr/~gildas/dist/gildas-src-${srcVersion}.tar.xz"
       "http://www.iram.fr/~gildas/dist/archive/gildas/gildas-src-${srcVersion}.tar.xz" ];
-    sha256 = "9faa0b3e674b5ffe5b1aee88027d7401a46ae28cd0b306595300547605d6222a";
+    sha256 = "0fb6iqwh4hm7v7sib7sx98vxdavn3d6q2gq6y6vxg2z29g31f8g2";
   };
 
   nativeBuildInputs = [ pkg-config groff perl getopt gfortran which ];