diff --git a/flake.nix b/flake.nix
index 31674d8..54f1567 100644
--- a/flake.nix
+++ b/flake.nix
@@ -163,11 +163,10 @@
                 "s|./src/|${websitePath}/var/www/|;/#!PROD-SNIP$/d" \
                 Caddyfile
 
+              # https://github.com/caddyserver/caddy/pull/5547#issuecomment-1555940637
               cat >> Caddyfile <<EOF
-              header {
-                -Last-modified
-                Etag "\"${builtins.baseNameOf websitePath}\""
-              }
+              header -Last-modified
+              header Etag \`"${builtins.baseNameOf websitePath}"\`
               EOF
 
               caddy fmt --overwrite Caddyfile