diff --git a/Gemfile b/Gemfile
index ecc252e979..79e23fa095 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,7 +9,7 @@ gem "benchmark"
 
 # locking to connection_pool 2.x until ActiveSupport's memcachestore supports the v3 API
 # see https://github.com/mperham/connection_pool/issues/212
-gem "connection_pool", "< 3"
+gem "connection_pool", "< 4"
 
 gem "pg"
 gem "puma"
diff --git a/Gemfile.lock b/Gemfile.lock
index 4db944cc3d..a5d8fdd384 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -194,7 +194,7 @@ GEM
     cgi (0.4.2)
     coderay (1.1.3)
     concurrent-ruby (1.3.6)
-    connection_pool (2.5.5)
+    connection_pool (3.0.2)
     crass (1.0.6)
     csv (3.3.5)
     cuprite (0.17)
@@ -721,7 +721,7 @@ DEPENDENCIES
   capybara
   civil_service!
   cloudwatch_scheduler!
-  connection_pool (< 3)
+  connection_pool (< 4)
   csv
   cuprite
   dalli