diff --git a/pkgs/by-name/si/signaturepdf/package.nix b/pkgs/by-name/si/signaturepdf/package.nix
index a152f87b3bc9..011d25f349bc 100644
--- a/pkgs/by-name/si/signaturepdf/package.nix
+++ b/pkgs/by-name/si/signaturepdf/package.nix
@@ -31,7 +31,7 @@ stdenv.mkDerivation rec {
     mkdir -p $out/share/signaturepdf $out/bin
 
     cp --target-directory=$out/share/signaturepdf --recursive \
-      app.php config locale public templates vendor
+      app.php config locale public templates vendor lib
 
     makeWrapper ${lib.getExe php} $out/bin/signaturepdf \
       --inherit-argv0 \