diff --git a/pkgs/tools/graphics/pikchr/default.nix b/pkgs/tools/graphics/pikchr/default.nix
index 432c70231d0d..ca4f647dfa2d 100644
--- a/pkgs/tools/graphics/pikchr/default.nix
+++ b/pkgs/tools/graphics/pikchr/default.nix
@@ -5,11 +5,12 @@
 
 stdenv.mkDerivation {
   pname = "pikchr";
-  version = "unstable-2021-04-07";
+  # To update, use the last check-in in https://pikchr.org/home/timeline?r=trunk
+  version = "unstable-2021-07-22";
 
   src = fetchurl {
-    url = "https://pikchr.org/home/tarball/90b6d5b4a3834ff0/pikchr.tar.gz";
-    sha256 = "1cqpnljy12gl82rcbb7mwhgv9szcliwkbwwh67hzdv020h1scxym";
+    url = "https://pikchr.org/home/tarball/d9e1502ed74c6aab/pikchr.tar.gz";
+    sha256 = "sha256-YSy95GiSodOS1YJgl9arBniqEJzYPrZ9CHNSCee9Yfg=";
   };
 
   # can't open generated html files