diff --git a/Gemfile.lock b/Gemfile.lock
index 2479ec1..cf316ce 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -2,7 +2,7 @@ PATH
   remote: .
   specs:
     middleman-images (0.2.0)
-      middleman-core (>= 4.1.14)
+      middleman-core (>= 4.1.14, < 5.1)
 
 GEM
   remote: https://rubygems.org/
@@ -12,8 +12,8 @@ GEM
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
-    addressable (2.7.0)
-      public_suffix (>= 2.0.2, < 5.0)
+    addressable (2.8.1)
+      public_suffix (>= 2.0.2, < 6.0)
     aruba (0.14.14)
       childprocess (>= 0.6.3, < 4.0.0)
       contracts (~> 0.9)
@@ -135,7 +135,7 @@ GEM
       activesupport (>= 3.1)
     parallel (1.19.1)
     progress (3.5.2)
-    public_suffix (4.0.3)
+    public_suffix (4.0.7)
     rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)