diff --git a/blog/builder.sh b/blog/builder.sh
index 8ab7ac3..6a5fe67 100644
--- a/blog/builder.sh
+++ b/blog/builder.sh
@@ -16,6 +16,5 @@ cp -r public/$publicPath/* $out/
 
 # Render math in HTML and XML files.
 node $server &
-SERVER_ID=$!
+sleep 1
 find $out/ -regex "$out/.*\.html" | xargs ruby $converter
-kill $SERVER_ID
diff --git a/blog/convert.rb b/blog/convert.rb
index 4c4420c..6fb86d7 100644
--- a/blog/convert.rb
+++ b/blog/convert.rb
@@ -6,7 +6,7 @@ require "json"
 def render_cached(cache, display, string, render_comment = nil)
   cache.fetch(string) do |new|
     puts "  Rendering #{render_comment || new}"
-    res = Net::HTTP.post URI("http://localhost:3000/render"),
+    res = Net::HTTP.post URI("http://localhost:8000/render"),
       { :equations => [ { :str => string, :display => display } ] }.to_json,
        "Content-Type" => "application/json"
     cache[string] = JSON.parse(res.body)[0]
diff --git a/blog/default.nix b/blog/default.nix
index 3a245eb..a7f3ecb 100644
--- a/blog/default.nix
+++ b/blog/default.nix
@@ -24,7 +24,7 @@ let
     server = ./katexserver.js;
     buildInputs = [
       hugo nodejs
-      requiredPackages.katex requiredPackages.express requiredPackages.body-parser
+      requiredPackages."katex-0.11.1" requiredPackages.express requiredPackages.body-parser
       (ruby.withPackages (ps: [ ps.nokogiri ]))
     ];
   };
diff --git a/blog/katexserver.js b/blog/katexserver.js
index c24814f..dc5ca0b 100644
--- a/blog/katexserver.js
+++ b/blog/katexserver.js
@@ -5,8 +5,7 @@ const bodyParser = require('body-parser');
 app = express();
 app.use(bodyParser.json());
 app.post('/render', (req, res) => {
-    console.log(req.body)
     res.send(req.body.equations.map(eq =>
         katex.renderToString(eq.str, { throwOnError: false, displayMode: eq.display })));
 });
-app.listen(3000);
+app.listen(8000);
diff --git a/blog/node-packages.nix b/blog/node-packages.nix
index 16807ed..4646c3c 100644
--- a/blog/node-packages.nix
+++ b/blog/node-packages.nix
@@ -457,13 +457,13 @@ let
   };
 in
 {
-  katex = nodeEnv.buildNodePackage {
+  "katex-0.11.1" = nodeEnv.buildNodePackage {
     name = "katex";
     packageName = "katex";
-    version = "0.12.0";
+    version = "0.11.1";
     src = fetchurl {
-      url = "https://registry.npmjs.org/katex/-/katex-0.12.0.tgz";
-      sha512 = "y+8btoc/CK70XqcHqjxiGWBOeIL8upbS0peTPXTvgrh21n1RiWWcIpSWM+4uXq+IAgNh9YYQWdc7LVDPDAEEAg==";
+      url = "https://registry.npmjs.org/katex/-/katex-0.11.1.tgz";
+      sha512 = "5oANDICCTX0NqYIyAiFCCwjQ7ERu3DQG2JFHLbYOf+fXaMoH8eg/zOq5WSYJsKMi/QebW+Eh3gSM+oss1H/bww==";
     };
     dependencies = [
       sources."commander-2.20.3"
diff --git a/blog/packages.json b/blog/packages.json
index e3fd054..52512e2 100644
--- a/blog/packages.json
+++ b/blog/packages.json
@@ -1,3 +1,3 @@
 [
-    "katex", "express", "body-parser"
+	{"katex": "0.11.1"}, "express", "body-parser"
 ]