diff --git a/Gemfile.lock b/Gemfile.lock
index d2c72fc2..433e7812 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -26,7 +26,7 @@ PATH
       filewatcher (~> 1.1.1)
       ice_nine (~> 0.11)
       redcarpet (~> 3.4)
-      sinatra (>= 1.4, < 3.0)
+      sinatra (>= 1.4, < 4.0)
       tzinfo (>= 1.1, < 3.0)
       tzinfo-data (~> 1.2018)
       zeitwerk (~> 2.1)
@@ -57,7 +57,7 @@ GEM
     json (2.3.1)
     method_source (0.9.0)
     mini_portile2 (2.5.1)
-    mustermann (1.1.1)
+    mustermann (2.0.2)
       ruby2_keywords (~> 0.0.1)
     nio4r (2.5.7)
     nokogiri (1.11.4)
@@ -75,7 +75,7 @@ GEM
     rack (2.2.3)
     rack-cors (1.1.0)
       rack (>= 2.0.0)
-    rack-protection (2.1.0)
+    rack-protection (2.2.3)
       rack
     rack-test (0.8.3)
       rack (>= 1.0, < 3)
@@ -100,7 +100,7 @@ GEM
     rspec-support (3.8.2)
     rspec_junit_formatter (0.4.1)
       rspec-core (>= 2, < 4, != 2.12.0)
-    ruby2_keywords (0.0.2)
+    ruby2_keywords (0.0.5)
     rubyzip (1.3.0)
     selenium-webdriver (3.142.7)
       childprocess (>= 0.5, < 4.0)
@@ -112,13 +112,13 @@ GEM
       json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.2)
-    sinatra (2.1.0)
-      mustermann (~> 1.0)
+    sinatra (2.2.3)
+      mustermann (~> 2.0)
       rack (~> 2.2)
-      rack-protection (= 2.1.0)
+      rack-protection (= 2.2.3)
       tilt (~> 2.0)
     thor (1.0.1)
-    tilt (2.0.10)
+    tilt (2.0.11)
     tzinfo (2.0.4)
       concurrent-ruby (~> 1.0)
     tzinfo-data (1.2020.4)
diff --git a/presenters.gemspec b/presenters.gemspec
index c5106fe8..db012152 100644
--- a/presenters.gemspec
+++ b/presenters.gemspec
@@ -24,7 +24,7 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency 'dry-container', '~>0.6'
   spec.add_runtime_dependency 'dry-configurable', '>0.1', '<= 7.0'
   spec.add_runtime_dependency 'dry-inflector', '~>0.1'
-  spec.add_runtime_dependency 'sinatra', '>=1.4', '< 3.0'
+  spec.add_runtime_dependency 'sinatra', '>=1.4', '<4.0'
   spec.add_runtime_dependency 'tzinfo', '>=1.1', '< 3.0'
   spec.add_runtime_dependency 'tzinfo-data', '~>1.2018'
   spec.add_runtime_dependency 'redcarpet', '~>3.4'