diff --git a/.github/workflows/crystal.yml b/.github/workflows/crystal.yml
new file mode 100644
index 0000000..ce9dbfc
--- /dev/null
+++ b/.github/workflows/crystal.yml
@@ -0,0 +1,22 @@
+name: Crystal CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    container:
+      image: crystallang/crystal
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install dependencies
+      run: shards install
+    - name: Run tests
+      run: crystal spec
diff --git a/shard.yml b/shard.yml
index ced5261..430c7b5 100644
--- a/shard.yml
+++ b/shard.yml
@@ -8,14 +8,13 @@ dependencies:
 development_dependencies:
   webmock:
     github: manastech/webmock.cr
-    version: 0.10.0
+    branch: master
   timecop:
-    github: waterlink/timecop.cr
-    version: ~> 0.1.0
+    github: crystal-community/timecop.cr
 
 authors:
   - Serdar Dogruyol <dogruyolserdar@gmail.com>
 
-crystal: 0.26.1
+crystal: 1.2.2
 
 license: MIT
diff --git a/spec/s3/presigned/html_printer_spec.cr b/spec/s3/presigned/html_printer_spec.cr
index 7da9914..171777e 100644
--- a/spec/s3/presigned/html_printer_spec.cr
+++ b/spec/s3/presigned/html_printer_spec.cr
@@ -9,7 +9,7 @@ module Aws
         end
 
         Spec.after_each do
-          Timecop.reset
+          # Timecop.reset
         end
 
         it "generates the same html each call" do
diff --git a/spec/s3/presigned/post_policy_spec.cr b/spec/s3/presigned/post_policy_spec.cr
index 936d64b..7cb2d87 100644
--- a/spec/s3/presigned/post_policy_spec.cr
+++ b/spec/s3/presigned/post_policy_spec.cr
@@ -7,7 +7,7 @@ module Aws
         describe "eq" do
           it "adds a field" do
             policy = Policy.new
-            policy.expiration(Time.now)
+            policy.expiration(Time.local)
             policy.condition("test", "test")
 
             policy.fields.size.should eq 1
@@ -15,7 +15,7 @@ module Aws
 
           it "returns self" do
             policy = Policy.new
-            policy.expiration(Time.now)
+            policy.expiration(Time.local)
 
             policy.condition("test", "test").should eq policy
           end
@@ -24,7 +24,7 @@ module Aws
         describe "valid?" do
           it "returns true if expiration is set" do
             policy = Policy.new
-            policy.expiration(Time.now)
+            policy.expiration(Time.local)
 
             policy.valid?.should be_true
           end
diff --git a/spec/s3/presigned/post_spec.cr b/spec/s3/presigned/post_spec.cr
index 44a2fcf..92efc68 100644
--- a/spec/s3/presigned/post_spec.cr
+++ b/spec/s3/presigned/post_spec.cr
@@ -9,7 +9,7 @@ module Aws
         end
 
         Spec.after_each do
-          Timecop.reset
+          # Timecop.reset
         end
 
         describe "valid?" do
@@ -19,7 +19,7 @@ module Aws
               aws_access_key: "test",
               aws_secret_key: "test"
             )
-            post.build { |b| b.condition("bucket", "t"); b.expiration(Time.now) }
+            post.build { |b| b.condition("bucket", "t"); b.expiration(Time.utc) }
 
             post.valid?.should be_true
           end
@@ -30,7 +30,7 @@ module Aws
               aws_access_key: "test",
               aws_secret_key: "test"
             )
-            post.build { |b| b.expiration(Time.now) }
+            post.build { |b| b.expiration(Time.utc) }
 
             post.valid?.should be_false
           end
@@ -148,7 +148,7 @@ module Aws
               aws_access_key: "test",
               aws_secret_key: "test"
             )
-            post.build { |b| b.expiration(Time.now) }
+            post.build { |b| b.expiration(Time.utc) }
 
             expect_raises(Exception) do
               post.url
@@ -161,7 +161,7 @@ module Aws
               aws_access_key: "test",
               aws_secret_key: "test"
             )
-            post.build { |b| b.expiration(Time.now); b.condition("bucket", "test") }
+            post.build { |b| b.expiration(Time.utc); b.condition("bucket", "test") }
 
             post.url.should eq("http://test.s3.amazonaws.com")
           end
@@ -174,7 +174,7 @@ module Aws
               aws_access_key: "test",
               aws_secret_key: "test"
             )
-            post.build { |b| b.expiration(Time.now) }
+            post.build { |b| b.expiration(Time.utc) }
 
             post.fields.should be_a(FieldCollection)
           end
@@ -189,7 +189,7 @@ module Aws
               signer: :v2
             )
             policy = nil
-            post.build { |p| p.expiration(Time.now); policy = p }
+            post.build { |p| p.expiration(Time.utc); policy = p }
 
             policy.should be_a(Policy)
             policy.as(Policy).fields["Signature"].should eq("vI0Km7fxOL7B9BunXFKM2/GvS1A=")
@@ -202,7 +202,7 @@ module Aws
               aws_secret_key: "test"
             )
             policy = nil
-            post.build { |p| p.expiration(Time.now); policy = p }
+            post.build { |p| p.expiration(Time.utc); policy = p }
 
             policy.should be_a(Policy)
             policy.as(Policy).fields["x-amz-signature"].should eq("7dc0bf8fe1dcc2344f8ceaf3148a8898fbac6f074ccbe4edfbfac545be693add")
diff --git a/spec/s3/presigned/url_spec.cr b/spec/s3/presigned/url_spec.cr
index dbac4d2..10cf0aa 100644
--- a/spec/s3/presigned/url_spec.cr
+++ b/spec/s3/presigned/url_spec.cr
@@ -76,7 +76,7 @@ module Aws
           end
 
           it "generates a correct url for v4" do
-            Timecop.freeze(Time.new(2013, 5, 24)) do
+            Timecop.freeze(Time.utc(2013, 5, 24)) do
               options = Url::Options.new(
                 region: "us-east-1",
                 aws_access_key: "AKIAIOSFODNN7EXAMPLE",
diff --git a/spec/spec_helper.cr b/spec/spec_helper.cr
index aed7a2f..13638b3 100644
--- a/spec/spec_helper.cr
+++ b/spec/spec_helper.cr
@@ -3,11 +3,11 @@ require "timecop"
 require "webmock"
 require "./s3/fixtures"
 
-struct Time
-  def self.utc_now
-    Timecop.now
-  end
-end
+#struct Time
+#  def self.utc_now
+#    Timecop.now
+#  end
+#end
 
 Spec.before_each do
   WebMock.reset
diff --git a/src/aws/s3/multipart_file_uploader.cr b/src/aws/s3/multipart_file_uploader.cr
index 4408536..970c7b7 100644
--- a/src/aws/s3/multipart_file_uploader.cr
+++ b/src/aws/s3/multipart_file_uploader.cr
@@ -57,8 +57,8 @@ module Aws::S3
       end
     end
 
-    private def compute_default_part_size(source_size)
-      [(source_size / 10_000).ceil, 5 * 1024 * 1024].max
+    private def compute_default_part_size(source_size) : Int32
+      [(source_size / 10_000).ceil, 5 * 1024 * 1024].max.to_i
     end
 
     private def part_size(total_size, part_size, offset)
diff --git a/src/aws/s3/paginators/list_object_v2.cr b/src/aws/s3/paginators/list_object_v2.cr
index 26d867f..f3eb5e3 100644
--- a/src/aws/s3/paginators/list_object_v2.cr
+++ b/src/aws/s3/paginators/list_object_v2.cr
@@ -30,7 +30,7 @@ module Aws::S3::Paginator
 
     # :nodoc:
     private def query_string
-      @params.map { |k, v| "#{k}=#{URI.escape(v.to_s)}" }.join("&")
+      @params.map { |k, v| "#{k}=#{URI.encode_www_form(v.to_s)}" }.join("&")
     end
   end
 end
diff --git a/src/aws/s3/presigned/form.cr b/src/aws/s3/presigned/form.cr
index ed14b25..ae6a144 100644
--- a/src/aws/s3/presigned/form.cr
+++ b/src/aws/s3/presigned/form.cr
@@ -16,7 +16,7 @@ module Aws
         #
         # ```
         # Aws::S3::Presigned::Form.build("us-east-1", "aws key", "aws secret") do |form|
-        #   form.expiration(Time.utc_now.to_unix + 1000)
+        #   form.expiration(Time.utc.to_unix + 1000)
         #   form.condition("bucket", "my bucket")
         #   form.condition("acl", "public-read")
         #   form.condition("key", "helloworld.png")
diff --git a/src/aws/s3/presigned/post.cr b/src/aws/s3/presigned/post.cr
index 0bdf6b2..56a25e4 100644
--- a/src/aws/s3/presigned/post.cr
+++ b/src/aws/s3/presigned/post.cr
@@ -67,7 +67,7 @@ module Aws
         private def add_fields_before_sign
           case @signer
           when :v4
-            time = Time.utc_now
+            time = Time.utc
             @policy.condition("x-amz-credential", credential_scope(time))
             @policy.condition("x-amz-algorithm", Awscr::Signer::ALGORITHM)
             @policy.condition("x-amz-date", time.to_s("%Y%m%dT%H%M%SZ"))
diff --git a/src/aws/s3/presigned/url.cr b/src/aws/s3/presigned/url.cr
index 9d02b2f..55b32f9 100644
--- a/src/aws/s3/presigned/url.cr
+++ b/src/aws/s3/presigned/url.cr
@@ -30,7 +30,7 @@ module Aws
 
           String.build do |str|
             str << "https://"
-            str << request.host
+            str << request.hostname
             str << request.resource
           end
         end
@@ -56,7 +56,7 @@ module Aws
           if @options.signer_version == :v4
             request.query_params.add("X-Amz-Expires", @options.expires.to_s)
           else
-            request.query_params.add("Expires", (Time.utc_now.to_unix + Time.unix(@options.expires).to_unix).to_s)
+            request.query_params.add("Expires", (Time.utc.to_unix + Time.unix(@options.expires).to_unix).to_s)
           end
 
           request