diff --git a/Gemfile.lock b/Gemfile.lock
index b9cc72ac4..c671469e6 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -221,7 +221,7 @@ GEM
       minitest (>= 5.0)
       ruby-progressbar
     mocha (1.11.2)
-    mock_redis (0.23.0)
+    mock_redis (0.24.0)
     msgpack (1.3.3)
     msgpack (1.3.3-x64-mingw32)
     multi_json (1.14.1)
diff --git a/app/models/saved_search.rb b/app/models/saved_search.rb
index 36478284f..722f47eb1 100644
--- a/app/models/saved_search.rb
+++ b/app/models/saved_search.rb
@@ -18,8 +18,7 @@ class SavedSearch < ApplicationRecord
         post_ids = Set.new
         queries.each do |query|
           redis_key = "search:#{query}"
-          # XXX change to `exists?` (ref: https://github.com-sds/mock_redis/pull/188
-          if redis.exists(redis_key)
+          if redis.exists?(redis_key)
             sub_ids = redis.smembers(redis_key).map(&:to_i)
             post_ids.merge(sub_ids)
           else