diff --git a/sinatra-contrib/sinatra-contrib.gemspec b/sinatra-contrib/sinatra-contrib.gemspec
index 3958b967..abb4f16d 100644
--- a/sinatra-contrib/sinatra-contrib.gemspec
+++ b/sinatra-contrib/sinatra-contrib.gemspec
@@ -217,7 +217,7 @@ Gem::Specification.new do |s|
   s.required_ruby_version = '>= 2.2.0'
 
   s.add_dependency "sinatra", Sinatra::VERSION
-  s.add_dependency "mustermann",  "1.0.0.beta1"
+  s.add_dependency "mustermann",  "1.0.0.beta2"
   s.add_dependency "backports", ">= 2.0"
   s.add_dependency "tilt",      ">= 1.3", "< 3"
   s.add_dependency "rack-test"
diff --git a/sinatra.gemspec b/sinatra.gemspec
index 1e789cc7..5899fc45 100644
--- a/sinatra.gemspec
+++ b/sinatra.gemspec
@@ -18,5 +18,5 @@ Gem::Specification.new 'sinatra', Sinatra::VERSION do |s|
   s.add_dependency 'rack', '~> 2.0'
   s.add_dependency 'tilt', '~> 2.0'
   s.add_dependency 'rack-protection', Sinatra::VERSION
-  s.add_dependency 'mustermann',  '1.0.0.beta1'
+  s.add_dependency 'mustermann',  '1.0.0.beta2'
 end