diff --git a/Gemfile b/Gemfile
index 30a832f..217688b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,5 +5,5 @@ group :development, :test do
   gem 'jekyll', '~> 3.8.6'
   gem 'jekyll-toc', '~> 0.12.2'
   #gem 'scss_lint', '~> 0.56.0', require: false
-  gem 'sinatra', '2.0.7' # for AJAX requests & pages with server-side logic
+  gem 'sinatra', '2.2.3' # for AJAX requests & pages with server-side logic
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index 1d0c06d..f340cb2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -40,7 +40,7 @@ GEM
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.3.6)
     mini_portile2 (2.6.1)
-    mustermann (1.1.1)
+    mustermann (2.0.2)
       ruby2_keywords (~> 0.0.1)
     nokogiri (1.12.5)
       mini_portile2 (~> 2.6.1)
@@ -49,8 +49,8 @@ GEM
       forwardable-extended (~> 2.6)
     public_suffix (4.0.6)
     racc (1.6.0)
-    rack (2.2.3)
-    rack-protection (2.0.7)
+    rack (2.2.4)
+    rack-protection (2.2.3)
       rack
     rake (13.0.6)
     rb-fsevent (0.11.1)
@@ -64,12 +64,12 @@ GEM
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
-    sinatra (2.0.7)
-      mustermann (~> 1.0)
-      rack (~> 2.0)
-      rack-protection (= 2.0.7)
+    sinatra (2.2.3)
+      mustermann (~> 2.0)
+      rack (~> 2.2)
+      rack-protection (= 2.2.3)
       tilt (~> 2.0)
-    tilt (2.0.10)
+    tilt (2.0.11)
 
 PLATFORMS
   ruby
@@ -78,7 +78,7 @@ DEPENDENCIES
   jekyll (~> 3.8.6)
   jekyll-toc (~> 0.12.2)
   rake (~> 13.0.1)
-  sinatra (= 2.0.7)
+  sinatra (= 2.2.3)
 
 BUNDLED WITH
    1.17.3