Gemfile in sup-1.0 vs Gemfile in sup-1.1

@@ -1,8 +1,12 @@
 source 'https://rubygems.org/'
 
 if !RbConfig::CONFIG['arch'].include?('openbsd')
   # update version in ext/mkrf_conf_xapian.rb as well.
-  gem 'xapian-ruby', '~> 1.2'
+  if /^2\.0\./ =~ RUBY_VERSION
+    gem 'xapian-ruby', ['~> 1.2', '< 1.3.6']
+  else
+    gem 'xapian-ruby', '~> 1.2'
+  end
 end
 
 gemspec