diff --git a/backend/Gemfile b/backend/Gemfile
index 2951a450..7aafca0e 100644
--- a/backend/Gemfile
+++ b/backend/Gemfile
@@ -19,7 +19,7 @@ gem "sprockets-rails"
 gem "active_model_serializers", "0.9.8"
 
 # Use postgresql and mongo as the database for Active Record
-gem "mongoid", "9.0.11" # https://www.mongodb.com/docs/mongoid/current/reference/compatibility/#rails-compatibility
+gem "mongoid", "9.1.0" # https://www.mongodb.com/docs/mongoid/current/reference/compatibility/#rails-compatibility
 gem "pg"
 
 # Use Puma as the app server
diff --git a/backend/Gemfile.lock b/backend/Gemfile.lock
index 84c7b47d..accaaaaf 100644
--- a/backend/Gemfile.lock
+++ b/backend/Gemfile.lock
@@ -99,7 +99,7 @@ GEM
       erubi (~> 1.4)
       parser (>= 2.4)
       smart_properties
-    bigdecimal (4.1.2)
+    bigdecimal (4.1.3)
     brakeman (6.1.2)
       racc
     bson (5.2.0)
@@ -266,10 +266,10 @@ GEM
     mini_mime (1.1.5)
     mini_portile2 (2.8.9)
     minitest (5.27.0)
-    mongo (2.25.0)
+    mongo (2.26.0)
       base64
       bson (>= 4.14.1, < 6.0.0)
-    mongoid (9.0.11)
+    mongoid (9.1.0)
       activemodel (>= 5.1, < 8.2, != 7.0.0)
       concurrent-ruby (>= 1.0.5, < 2.0)
       mongo (>= 2.18.0, < 3.0.0)
@@ -544,7 +544,7 @@ DEPENDENCIES
   kaminari-actionview
   kaminari-mongoid
   letter_opener
-  mongoid (= 9.0.11)
+  mongoid (= 9.1.0)
   mongoid-rspec
   nearest_time_zone
   omniauth (~> 1.8)