diff --git a/lib/mondrian_redis_segment_cache/cache.rb b/lib/mondrian_redis_segment_cache/cache.rb
index 4bfa3d9..cbdd83c 100644
--- a/lib/mondrian_redis_segment_cache/cache.rb
+++ b/lib/mondrian_redis_segment_cache/cache.rb
@@ -108,7 +108,7 @@ def reload
 
       mondrian_redis.with do |connection|
         connection.sscan_each(SEGMENT_HEADERS_SET_KEY) do |segment_header_base64|
-          unless connection.exists(segment_header_base64)
+          unless connection.exists?(segment_header_base64)
             connection.srem(SEGMENT_HEADERS_SET_KEY, segment_header_base64)
             next
           end
diff --git a/mondrian_redis_segment_cache.gemspec b/mondrian_redis_segment_cache.gemspec
index 1aa85a9..34f4314 100644
--- a/mondrian_redis_segment_cache.gemspec
+++ b/mondrian_redis_segment_cache.gemspec
@@ -18,7 +18,7 @@ Gem::Specification.new do |gem|
   gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
   gem.require_paths = ["lib"]
 
-  gem.add_dependency "redis"
+  gem.add_dependency "redis", "> 3"
   gem.add_dependency "java_to_base64"
   gem.add_dependency "mondrian-olap"
   gem.add_dependency "concurrent-ruby"