diff --git a/.pkg b/.pkg
index 8754d9f..82de56f 100644
--- a/.pkg
+++ b/.pkg
@@ -1,7 +1,7 @@
 [boost]
   url=git@github.com:motis-project/boost.git
   branch=master
-  commit=60cae66449fa3c9599b2b7d3d5d44c65301ed3a3
+  commit=73549ebca677fe6214202a1ab580362b4f80e653
 [osmium]
   url=git@github.com:motis-project/libosmium.git
   branch=master
@@ -17,7 +17,7 @@
 [cista]
   url=git@github.com:felixguendling/cista.git
   branch=master
-  commit=777618a9a96a9bfbf44edc64686c0c17eb1afd05
+  commit=5b2ca78d1af99941ea41e195dc3a29b4f05e1b77
 [googletest]
   url=git@github.com:motis-project/googletest.git
   branch=master
@@ -30,14 +30,14 @@
   url=git@github.com:motis-project/protozero.git
   branch=master
   commit=8c9f3fa97c2cfdceef86d0b61818ae98e9328f29
-[zlib]
-  url=git@github.com:motis-project/zlib.git
-  branch=master
-  commit=8e7c86d3a0e49101b9a67d74c4a07345dcb0e485
+[zlib-ng]
+  url=git@github.com:motis-project/zlib-ng.git
+  branch=develop
+  commit=68ab3e2d80253ec5dc3c83691d9ff70477b32cd3
 [tiles]
   url=git@github.com:motis-project/tiles.git
   branch=master
-  commit=649e1c190e63b2d0de5cbc693093355fa0476010
+  commit=f7208d4e05661abbf09e4f284de0112a445f6b0a
 [mimalloc]
   url=git@github.com:motis-project/mimalloc.git
   branch=master
@@ -65,4 +65,4 @@
 [net]
   url=git@github.com:motis-project/net.git
   branch=master
-  commit=44674d2f3917e20b7019a0f7254d332522c36fb7
+  commit=75611343512242c64a5b3f50f3a660a17298339d
diff --git a/exe/backend/src/http_server.cc b/exe/backend/src/http_server.cc
index 8e37ed0..f1b35ca 100644
--- a/exe/backend/src/http_server.cc
+++ b/exe/backend/src/http_server.cc
@@ -210,9 +210,12 @@ struct http_server::impl {
 
   void handle_static(web_server::http_req_t const& req,
                      web_server::http_res_cb_t const& cb) {
-    if (!serve_static_files_ ||
-        !net::serve_static_file(static_file_path_, req, cb)) {
-      return cb(net::not_found_response(req));
+    if (auto res = net::serve_static_file(static_file_path_, req);
+        res.has_value()) {
+      cb(std::move(*res));
+    } else {
+      namespace http = boost::beast::http;
+      cb(net::web_server::string_res_t{http::status::not_found, req.version()});
     }
   }
 
diff --git a/include/osr/types.h b/include/osr/types.h
index 1793035..d691d3f 100644
--- a/include/osr/types.h
+++ b/include/osr/types.h
@@ -144,7 +144,7 @@ constexpr level_t to_level(float const f) {
 }
 
 constexpr float to_float(level_t const l) {
-  return kMinLevel + (to_idx(l) / 4.0F);
+  return l == level_t::invalid() ? 0.0F : (kMinLevel + (to_idx(l) / 4.0F));
 }
 
 constexpr auto const kLevelBits = cista::constexpr_trailing_zeros(