diff --git a/Gemfile b/Gemfile
index 08a928b..0321fe0 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,7 +4,7 @@ gem 'heroku'
 
 group :development do
   gem 'rake', '~> 0.9.2'
-  gem 'rack', '~> 1.4.1'
+  gem 'rack', '~> 3.1.8'
   gem 'jekyll', '~> 0.11.2'
   gem 'rdiscount', '~> 1.6.8'
   gem 'pygments.rb', '~> 0.2.12'
@@ -17,4 +17,4 @@ group :development do
   gem 'liquid', '~> 2.3.0'
 end
 
-gem 'sinatra', '~> 1.3.2'
+gem 'sinatra', '~> 4.1.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index 0bde2e6..8f9e680 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -5,6 +5,7 @@ GEM
     addressable (2.3.2)
     albino (1.3.3)
       posix-spawn (>= 0.3.6)
+    base64 (0.2.0)
     blankslate (2.1.2.4)
     chunky_png (1.2.5)
     classifier (1.3.3)
@@ -38,34 +39,45 @@ GEM
     launchy (2.1.1)
       addressable (~> 2.3)
     liquid (2.3.0)
+    logger (1.6.1)
     maruku (0.6.0)
       syntax (>= 1.0.0)
     mime-types (1.19)
+    mustermann (3.0.3)
+      ruby2_keywords (~> 0.0.1)
     netrc (0.7.5)
     posix-spawn (0.3.6)
     pygments.rb (0.2.13)
       rubypython (~> 0.5.3)
-    rack (1.4.1)
-    rack-protection (1.2.0)
-      rack
+    rack (3.1.8)
+    rack-protection (4.1.0)
+      base64 (>= 0.1.0)
+      logger (>= 1.6.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.0.0)
+      rack (>= 3.0.0)
     rake (0.9.2.2)
     rb-fsevent (0.9.1)
     rdiscount (1.6.8)
     rest-client (1.6.7)
       mime-types (>= 1.16)
+    ruby2_keywords (0.0.5)
     rubypants (0.2.0)
     rubypython (0.5.3)
       blankslate (>= 2.1.2.3)
       ffi (~> 1.0.7)
     rubyzip (0.9.9)
     sass (3.1.20)
-    sinatra (1.3.2)
-      rack (~> 1.3, >= 1.3.6)
-      rack-protection (~> 1.2)
-      tilt (~> 1.3, >= 1.3.3)
+    sinatra (4.1.0)
+      logger (>= 1.6.0)
+      mustermann (~> 3.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.1.0)
+      rack-session (>= 2.0.0, < 3)
+      tilt (~> 2.0)
     stringex (1.4.0)
     syntax (1.0.0)
-    tilt (1.3.3)
+    tilt (2.4.0)
 
 PLATFORMS
   ruby
@@ -78,10 +90,10 @@ DEPENDENCIES
   jekyll (~> 0.11.2)
   liquid (~> 2.3.0)
   pygments.rb (~> 0.2.12)
-  rack (~> 1.4.1)
+  rack (~> 3.1.8)
   rake (~> 0.9.2)
   rb-fsevent (~> 0.9)
   rdiscount (~> 1.6.8)
   rubypants (~> 0.2.0)
-  sinatra (~> 1.3.2)
+  sinatra (~> 4.1.0)
   stringex (~> 1.4.0)