diff --git a/Gemfile.lock b/Gemfile.lock
index f1ce0fb..ba07a3c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -50,6 +50,7 @@ GEM
     llhttp-ffi (0.5.0)
       ffi-compiler (~> 1.0)
       rake (~> 13.0)
+    logger (1.6.1)
     mail (2.8.1)
       mini_mime (>= 0.1.1)
       net-imap
@@ -80,13 +81,16 @@ GEM
       minitest (>= 5.0)
       sexpr (~> 1.1)
     public_suffix (5.0.5)
-    rack (2.2.9)
-    rack-protection (3.2.0)
+    rack (3.1.8)
+    rack-protection (4.1.0)
       base64 (>= 0.1.0)
-      rack (~> 2.2, >= 2.2.4)
+      logger (>= 1.6.0)
+      rack (>= 3.0.0, < 4)
     rack-proxy (0.7.7)
       rack
     rack-robustness (1.2.0)
+    rack-session (2.0.0)
+      rack (>= 3.0.0)
     rack-test (2.1.0)
       rack (>= 1.3)
     rake (13.2.1)
@@ -110,12 +114,14 @@ GEM
       rspec-core (>= 2, < 4, != 2.12.0)
     ruby2_keywords (0.0.5)
     sexpr (1.1.0)
-    sinatra (3.2.0)
+    sinatra (4.1.0)
+      logger (>= 1.6.0)
       mustermann (~> 3.0)
-      rack (~> 2.2, >= 2.2.4)
-      rack-protection (= 3.2.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.1.0)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
-    tilt (2.3.0)
+    tilt (2.4.0)
     timeout (0.4.1)
 
 PLATFORMS
@@ -128,7 +134,7 @@ DEPENDENCIES
   rake (~> 13)
   rspec (~> 3.10)
   rspec_junit_formatter (>= 0.6, < 0.7)
-  sinatra (> 3.0, < 4.0)
+  sinatra (> 3.0, < 5.0)
   webspicy!
 
 BUNDLED WITH
diff --git a/webspicy.gemspec b/webspicy.gemspec
index a24a842..a9a34f5 100644
--- a/webspicy.gemspec
+++ b/webspicy.gemspec
@@ -18,7 +18,7 @@ Gem::Specification.new do |s|
   s.executables = (Dir["bin/*"]).collect{|f| File.basename(f)}
 
   s.add_development_dependency "rake", "~> 13"
-  s.add_development_dependency 'sinatra', '> 3.0', '< 4.0'
+  s.add_development_dependency 'sinatra', '> 3.0', '< 5.0'
   s.add_development_dependency "rspec", "~> 3.10"
   s.add_development_dependency 'rspec_junit_formatter', '>= 0.6', '< 0.7'