diff --git a/Gemfile.lock b/Gemfile.lock
index 07e5c541..d4c02771 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -176,10 +176,10 @@ GEM
     diff-lcs (1.5.1)
     docile (1.4.0)
     domain_name (0.6.20240107)
-    dotenv (2.8.1)
-    dotenv-rails (2.8.1)
-      dotenv (= 2.8.1)
-      railties (>= 3.2)
+    dotenv (3.1.0)
+    dotenv-rails (3.1.0)
+      dotenv (= 3.1.0)
+      railties (>= 6.1)
     erubi (1.12.0)
     execjs (2.9.1)
     factory_bot (6.4.6)
diff --git a/spec/controllers/conference_registration_controller_spec.rb b/spec/controllers/conference_registration_controller_spec.rb
index 5ed47c1f..62162e13 100644
--- a/spec/controllers/conference_registration_controller_spec.rb
+++ b/spec/controllers/conference_registration_controller_spec.rb
@@ -12,7 +12,7 @@ describe ConferenceRegistrationsController, type: :controller do
   shared_examples 'access #new action' do |user, ichain, path, message|
     before :each do
       sign_in send(user) if user
-      stub_const('ENV', ENV.to_hash.merge('OSEM_ICHAIN_ENABLED' => ichain))
+      ENV['OSEM_ICHAIN_ENABLED'] = ichain
       get :new, params: { conference_id: conference.short_title }
     end
 
@@ -28,7 +28,7 @@ describe ConferenceRegistrationsController, type: :controller do
   shared_examples 'can access #new action' do |user, ichain|
     before :each do
       sign_in send(user) if user
-      stub_const('ENV', ENV.to_hash.merge('OSEM_ICHAIN_ENABLED' => ichain))
+      ENV['OSEM_ICHAIN_ENABLED'] = ichain
       get :new, params: { conference_id: conference.short_title }
     end