diff --git a/lib/github_changelog_generator/options.rb b/lib/github_changelog_generator/options.rb
index 6b456ce..5c4a958 100644
--- a/lib/github_changelog_generator/options.rb
+++ b/lib/github_changelog_generator/options.rb
@@ -52,11 +52,6 @@ module GitHubChangelogGenerator
       :verbose
     ]
 
-    THESE_ARE_DIFFERENT = [
-      :tag1,
-      :tag2
-    ]
-
     def initialize(values)
       super(values)
       unsupported_options.any? && raise(UnsupportedOptionError, unsupported_options.inspect)
@@ -78,15 +73,11 @@ module GitHubChangelogGenerator
     end
 
     def unsupported_options
-      values.keys - supported_options
+      values.keys - KNOWN_OPTIONS
     end
 
     def supported_option?(key)
-      supported_options.include?(key)
-    end
-
-    def supported_options
-      KNOWN_OPTIONS + THESE_ARE_DIFFERENT
+      KNOWN_OPTIONS.include?(key)
     end
   end
 end
diff --git a/lib/github_changelog_generator/parser.rb b/lib/github_changelog_generator/parser.rb
index 0d82891..4c836cf 100755
--- a/lib/github_changelog_generator/parser.rb
+++ b/lib/github_changelog_generator/parser.rb
@@ -191,8 +191,6 @@ module GitHubChangelogGenerator
     # @return [Hash] Default options
     def self.default_options
       Options.new(
-        tag1: nil,
-        tag2: nil,
         date_format: "%Y-%m-%d",
         output: "CHANGELOG.md",
         base: "HISTORY.md",