diff --git a/shard.yml b/shard.yml
index d605e2c..428149a 100644
--- a/shard.yml
+++ b/shard.yml
@@ -18,7 +18,7 @@ dependencies:
 development_dependencies:
   ameba:
     github: crystal-ameba/ameba
-    version: ~> 0.10.0
+    version: ~> 0.12.0
 
 crystal: 0.30.0
 
diff --git a/spec/route_handler_spec.cr b/spec/route_handler_spec.cr
index 4ec111b..93cf0f0 100644
--- a/spec/route_handler_spec.cr
+++ b/spec/route_handler_spec.cr
@@ -10,6 +10,17 @@ describe "Kemal::RouteHandler" do
     client_response.body.should eq("hello")
   end
 
+  it "routes with long response body" do
+    long_response_body = "string" * 10_000
+
+    get "/" do
+      long_response_body
+    end
+    request = HTTP::Request.new("GET", "/")
+    client_response = call_request_on_app(request)
+    client_response.body.should eq(long_response_body)
+  end
+
   it "routes should only return strings" do
     get "/" do
       100
diff --git a/spec/run_spec.cr b/spec/run_spec.cr
index 818cbe9..ec89d23 100644
--- a/spec/run_spec.cr
+++ b/spec/run_spec.cr
@@ -5,12 +5,12 @@ private def run(code)
     require "./src/kemal"
     #{code}
     CR
-  String.build do |stdout|
-    stderr = String.build do |io|
-      Process.new("crystal", ["eval"], input: IO::Memory.new(code), output: stdout, error: io).wait
-    end
-    fail(stderr) unless stderr.empty?
-  end
+
+  stdout = IO::Memory.new
+  stderr = IO::Memory.new
+  status = Process.new("crystal", ["eval"], input: IO::Memory.new(code), output: stdout, error: stderr).wait
+  fail(stderr.to_s) unless status.success?
+  stdout.to_s
 end
 
 describe "Run" do
diff --git a/spec/spec_helper.cr b/spec/spec_helper.cr
index 0bc127a..803aacf 100644
--- a/spec/spec_helper.cr
+++ b/spec/spec_helper.cr
@@ -48,6 +48,9 @@ def create_ws_request_and_return_io_and_context(handler, request)
   rescue IO::Error
     # Raises because the IO::Memory is empty
   end
+  {% if compare_versions(Crystal::VERSION, "0.35.0-0") >= 0 %}
+    response.upgrade_handler.try &.call(io)
+  {% end %}
   io.rewind
   {io, context}
 end
diff --git a/src/kemal/ext/response.cr b/src/kemal/ext/response.cr
index faf9db1..6fd4c01 100644
--- a/src/kemal/ext/response.cr
+++ b/src/kemal/ext/response.cr
@@ -8,7 +8,7 @@ class HTTP::Server::Response
 
       ensure_headers_written
 
-      super
+      previous_def
     end
   end
 end
diff --git a/src/kemal/helpers/helpers.cr b/src/kemal/helpers/helpers.cr
index 7f14755..bf212a2 100644
--- a/src/kemal/helpers/helpers.cr
+++ b/src/kemal/helpers/helpers.cr
@@ -1,5 +1,7 @@
-require "flate"
-require "gzip"
+{% if compare_versions(Crystal::VERSION, "0.35.0-0") >= 0 %}
+  require "compress/deflate"
+  require "compress/gzip"
+{% end %}
 require "mime"
 
 # Adds given `Kemal::Handler` to handlers chain.
@@ -142,14 +144,26 @@ def send_file(env : HTTP::Server::Context, path : String, mime_type : String? =
     condition = config.is_a?(Hash) && config["gzip"]? == true && filesize > minsize && Kemal::Utils.zip_types(file_path)
     if condition && request_headers.includes_word?("Accept-Encoding", "gzip")
       env.response.headers["Content-Encoding"] = "gzip"
-      Gzip::Writer.open(env.response) do |deflate|
-        IO.copy(file, deflate)
-      end
+      {% if compare_versions(Crystal::VERSION, "0.35.0-0") >= 0 %}
+        Compress::Gzip::Writer.open(env.response) do |deflate|
+          IO.copy(file, deflate)
+        end
+      {% else %}
+        Gzip::Writer.open(env.response) do |deflate|
+          IO.copy(file, deflate)
+        end
+      {% end %}
     elsif condition && request_headers.includes_word?("Accept-Encoding", "deflate")
       env.response.headers["Content-Encoding"] = "deflate"
-      Flate::Writer.open(env.response) do |deflate|
-        IO.copy(file, deflate)
-      end
+      {% if compare_versions(Crystal::VERSION, "0.35.0-0") >= 0 %}
+        Compress::Deflate::Writer.open(env.response) do |deflate|
+          IO.copy(file, deflate)
+        end
+      {% else %}
+        Flate::Writer.open(env.response) do |deflate|
+          IO.copy(file, deflate)
+        end
+      {% end %}
     else
       env.response.content_length = filesize
       IO.copy(file, env.response)
diff --git a/src/kemal/static_file_handler.cr b/src/kemal/static_file_handler.cr
index 7f3e061..109e971 100644
--- a/src/kemal/static_file_handler.cr
+++ b/src/kemal/static_file_handler.cr
@@ -1,7 +1,3 @@
-{% if !flag?(:without_zlib) %}
-  require "zlib"
-{% end %}
-
 module Kemal
   class StaticFileHandler < HTTP::StaticFileHandler
     # ameba:disable Metrics/CyclomaticComplexity
diff --git a/src/kemal/websocket_handler.cr b/src/kemal/websocket_handler.cr
index 469979a..03aed1a 100644
--- a/src/kemal/websocket_handler.cr
+++ b/src/kemal/websocket_handler.cr
@@ -31,9 +31,7 @@ module Kemal
 
     def call(context : HTTP::Server::Context)
       return call_next(context) unless context.ws_route_found? && websocket_upgrade_request?(context)
-      content = context.websocket.call(context)
-      context.response.print(content)
-      context
+      context.websocket.call(context)
     end
 
     def lookup_ws_route(path : String)