diff --git a/.github/workflows/hex-publish.yml b/.github/workflows/hex-publish.yml
deleted file mode 100644
index f904b66..0000000
--- a/.github/workflows/hex-publish.yml
+++ /dev/null
@@ -1,18 +0,0 @@
-name: Hex Publish
-
-on:
-  push:
-    tags:
-      - '*'
-
-jobs:
-  publish:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Check out
-        uses: actions/checkout@v2
-
-      - name: Publish to Hex.pm
-        uses: erlangpack/github-action@v3
-        env:
-          HEX_API_KEY: ${{ secrets.HEX_API_KEY }}
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index bbfd9a5..67cc33b 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -18,7 +18,7 @@ jobs:
 
     strategy:
       matrix:
-        otp_version: [23,24,25]
+        otp_version: [24,25,26]
         os: [ubuntu-latest]
 
     container:
diff --git a/src/cowmachine.app.src b/src/cowmachine.app.src
index bd3bbe2..96061f3 100644
--- a/src/cowmachine.app.src
+++ b/src/cowmachine.app.src
@@ -6,12 +6,13 @@
   {applications, [
                   kernel,
                   stdlib,
+                  inets,
                   zotonic_stdlib,
+                  ranch,
+                  cowlib,
                   cowboy
                  ]},
-  {env, [
-        {use_sendfile, erlang}
-  ]},
+  {env, []},
   {licenses, ["Apache-2.0"]},
   {links, [{"GitHub", "https://github.com/zotonic/cowmachine"}]}
  ]}.
diff --git a/src/cowmachine_decision_core.erl b/src/cowmachine_decision_core.erl
index 1b6f7d1..357c5af 100644
--- a/src/cowmachine_decision_core.erl
+++ b/src/cowmachine_decision_core.erl
@@ -82,10 +82,12 @@ is_cacheable(generate_etag) -> true;
 is_cacheable(_) -> false.
 
 -spec controller_call_process(ContentType, State, Context) -> Result when
-	ContentType :: cow_http_hd:media_type(), 
-	State :: cmstate(), 
+	ContentType :: cow_http_hd:media_type(),
+	State :: cmstate(),
 	Context :: cowmachine_req:context(),
-	Result :: {boolean() | ContentType, State, Context}.
+	Result :: {Res, State, Context},
+    Res :: boolean() | cowmachine_req:halt() | {error, any(), any()} | {error, any()} |
+            cowmachine_req:resp_body().
 controller_call_process(ContentType, State, Context) ->
     {T, Context1} = cowmachine_controller:do_process(ContentType, State, Context),
     {T, State, Context1}.
@@ -137,11 +139,18 @@ respond(Code, State, Context) ->
                                     ExpCtx0)
             end,
             {StateExp, ExpCtx};
-        % Let the error controller handle 4xx and 5xx errors
-        E when E =:= 401; E =:= 403; E =:= 404; E=:= 410;
-               (E >= 500 andalso E =< 599) ->
-            controller_call(finish_request, State, Context),
-            throw({stop_request, Code});
+        E when E =:= 401; E =:= 403; E =:= 404; E=:= 410; (E >= 500 andalso E =< 599) ->
+            % Http errors - maybe handled by error controller
+            HasRespContentType = cowmachine_req:get_resp_header(<<"content-type">>, Context) =/= undefined,
+            HasBody = cowmachine_req:resp_body(Context) =/= undefined,
+            if
+                HasBody andalso HasRespContentType ->
+                    {State, Context};
+                true ->
+                    % Let the error controller handle 4xx and 5xx errors without body
+                    controller_call(finish_request, State, Context),
+                    throw({stop_request, Code})
+            end;
         _ ->
             {State, Context}
     end,
@@ -778,9 +787,9 @@ process_helper(ContentTypeAccepted, State, Context) ->
         {halt, _} -> Result;
         {error, _, _} -> Result;
         {error, _} -> Result;
-        true when is_boolean(Res) -> Result;
-        false when is_boolean(Res)  -> Result;
-        RespBody ->
+        true -> Result;
+        false -> Result;
+        RespBody when is_binary(RespBody); is_list(RespBody) ->
             C3 = cowmachine_req:set_resp_body(RespBody, C2),
             {body, S2, C3}
     end.
diff --git a/src/cowmachine_response.erl b/src/cowmachine_response.erl
index 6b3b158..c50ffd7 100644
--- a/src/cowmachine_response.erl
+++ b/src/cowmachine_response.erl
@@ -356,7 +356,7 @@ send_device_body(Context, Length, IO) ->
 -spec send_file_body(Context, Length, File, FinNoFin) -> Result when
 	Context :: cowmachine_req:context(),
 	Length :: non_neg_integer(), 
-	File :: Filename | file:iodata(),
+	File :: Filename | iodata(),
 	Filename :: file:name_all(),
 	FinNoFin :: fin | nofin,
 	Result :: cowmachine_req:context().
diff --git a/src/cowmachine_util.erl b/src/cowmachine_util.erl
index 1c4f514..b20438a 100644
--- a/src/cowmachine_util.erl
+++ b/src/cowmachine_util.erl
@@ -239,7 +239,7 @@ accept_header_to_media_types(HeadVal) ->
 
 -spec normalize_provided(Provided) -> Result when
 	Provided :: [cowmachine_req:media_type()],
-	Result :: cow_http_hd:media_type().
+	Result :: [cow_http_hd:media_type()].
 normalize_provided(Provided) ->
     [ normalize_content_type(X) || X <- Provided ].