diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7ce8ed1..47a7cb7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,7 +16,7 @@ jobs:
           - '3.0'
           - 3.1
           - 3.2
-          - '3.3.0-preview2'
+          - 3.3
     runs-on: ${{ matrix.os }}
     env:
       LOKALISE_API_TOKEN: 123abc
diff --git a/lib/ruby_lokalise_api/collections/base.rb b/lib/ruby_lokalise_api/collections/base.rb
index d0cb375..7fbcbea 100644
--- a/lib/ruby_lokalise_api/collections/base.rb
+++ b/lib/ruby_lokalise_api/collections/base.rb
@@ -86,7 +86,7 @@ def reinit_endpoint(req_params: @self_endpoint.req_params, override_req_params:
 
       def populate_common_attrs_from(response)
         supported_attrs.each do |attrib|
-          instance_variable_set "@#{attrib}", response.content[attrib]
+          instance_variable_set :"@#{attrib}", response.content[attrib]
         end
 
         headers = response.headers
diff --git a/lib/ruby_lokalise_api/endpoints/base_endpoint.rb b/lib/ruby_lokalise_api/endpoints/base_endpoint.rb
index 7293bb9..e315f80 100644
--- a/lib/ruby_lokalise_api/endpoints/base_endpoint.rb
+++ b/lib/ruby_lokalise_api/endpoints/base_endpoint.rb
@@ -38,7 +38,7 @@ def full_uri
       # Creates methods like `do_post`, `do_get` that proxy calls to the
       # corresponding methods in the `Request` module
       HTTP_METHODS.each do |method_postfix|
-        define_method "do_#{method_postfix}" do
+        define_method :"do_#{method_postfix}" do
           send method_postfix, self
         end
       end
diff --git a/lib/ruby_lokalise_api/endpoints/main_endpoint.rb b/lib/ruby_lokalise_api/endpoints/main_endpoint.rb
index ff36274..0014e22 100644
--- a/lib/ruby_lokalise_api/endpoints/main_endpoint.rb
+++ b/lib/ruby_lokalise_api/endpoints/main_endpoint.rb
@@ -6,7 +6,7 @@ class MainEndpoint < BaseEndpoint
       BASE_URL = 'https://api.lokalise.com/api2'
 
       def initialize(client, params = {})
-        super client, params
+        super(client, params)
 
         @uri = partial_uri(base_query(*@query_params))
       end
diff --git a/lib/ruby_lokalise_api/endpoints/oauth2/oauth2_endpoint.rb b/lib/ruby_lokalise_api/endpoints/oauth2/oauth2_endpoint.rb
index 390d7fd..f340205 100644
--- a/lib/ruby_lokalise_api/endpoints/oauth2/oauth2_endpoint.rb
+++ b/lib/ruby_lokalise_api/endpoints/oauth2/oauth2_endpoint.rb
@@ -8,7 +8,7 @@ class OAuth2Endpoint < BaseEndpoint
         PARTIAL_URI_TEMPLATE = '{/segments*}{?query*}'
 
         def initialize(client, params = {})
-          super client, params
+          super(client, params)
 
           @uri = partial_uri(base_query(*@query_params), params.fetch(:get, []))
         end
diff --git a/lib/ruby_lokalise_api/generics.rb b/lib/ruby_lokalise_api/generics.rb
index fc500ff..6e08aa9 100644
--- a/lib/ruby_lokalise_api/generics.rb
+++ b/lib/ruby_lokalise_api/generics.rb
@@ -14,7 +14,7 @@ class Generics
 
     def initialize(raw_data)
       raw_data.each do |att, val|
-        instance_variable_set "@#{att}", val
+        instance_variable_set :"@#{att}", val
 
         self.class.class_exec do
           attr_reader att.to_sym
diff --git a/lib/ruby_lokalise_api/resources/base.rb b/lib/ruby_lokalise_api/resources/base.rb
index bb0634d..dcf6c0c 100644
--- a/lib/ruby_lokalise_api/resources/base.rb
+++ b/lib/ruby_lokalise_api/resources/base.rb
@@ -49,7 +49,7 @@ def delegate_call(from, to = nil)
 
       def read_main_params
         self.class.const_get(:MAIN_PARAMS).to_array.map do |param|
-          instance_variable_get "@#{param}"
+          instance_variable_get :"@#{param}"
         end
       end
 
@@ -69,7 +69,7 @@ def populate_attrs_from(content)
                     content[attrib]
                   end
 
-          instance_variable_set "@#{attrib}", value
+          instance_variable_set :"@#{attrib}", value
         end
       end
     end