diff --git a/db/migrate/20160627122446_create_surveys.rb b/db/migrate/20160627122446_create_surveys.rb
index ca7f52ea..9fdfd30d 100644
--- a/db/migrate/20160627122446_create_surveys.rb
+++ b/db/migrate/20160627122446_create_surveys.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreateSurveys < ActiveRecord::Migration
+class CreateSurveys < ActiveRecord::Migration[5.0]
   def change
     create_table :surveys do |t|
       t.datetime :start_date
diff --git a/db/migrate/20160628093634_create_survey_questions.rb b/db/migrate/20160628093634_create_survey_questions.rb
index 63020a7d..b89dd3b2 100644
--- a/db/migrate/20160628093634_create_survey_questions.rb
+++ b/db/migrate/20160628093634_create_survey_questions.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreateSurveyQuestions < ActiveRecord::Migration
+class CreateSurveyQuestions < ActiveRecord::Migration[5.0]
   def change
     create_table :survey_questions do |t|
       t.references :survey
diff --git a/db/migrate/20160629145954_add_target_to_surveys.rb b/db/migrate/20160629145954_add_target_to_surveys.rb
index 385ea38a..e0efc45d 100644
--- a/db/migrate/20160629145954_add_target_to_surveys.rb
+++ b/db/migrate/20160629145954_add_target_to_surveys.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddTargetToSurveys < ActiveRecord::Migration
+class AddTargetToSurveys < ActiveRecord::Migration[5.0]
   def change
     add_column :surveys, :target, :integer, default: 0
   end
diff --git a/db/migrate/20160630094850_create_survey_replies.rb b/db/migrate/20160630094850_create_survey_replies.rb
index 8e8d43a2..fb8f3b83 100644
--- a/db/migrate/20160630094850_create_survey_replies.rb
+++ b/db/migrate/20160630094850_create_survey_replies.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreateSurveyReplies < ActiveRecord::Migration
+class CreateSurveyReplies < ActiveRecord::Migration[5.0]
   def change
     create_table :survey_replies do |t|
       t.integer :survey_question_id
diff --git a/db/migrate/20160630130731_create_survey_submissions.rb b/db/migrate/20160630130731_create_survey_submissions.rb
index a64c4e5d..35a89fc8 100644
--- a/db/migrate/20160630130731_create_survey_submissions.rb
+++ b/db/migrate/20160630130731_create_survey_submissions.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreateSurveySubmissions < ActiveRecord::Migration
+class CreateSurveySubmissions < ActiveRecord::Migration[5.0]
   def change
     create_table :survey_submissions do |t|
       t.integer :user_id
diff --git a/db/migrate/20161229080315_add_comments_count_to_events.rb b/db/migrate/20161229080315_add_comments_count_to_events.rb
index 25e9ed58..b886b079 100644
--- a/db/migrate/20161229080315_add_comments_count_to_events.rb
+++ b/db/migrate/20161229080315_add_comments_count_to_events.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddCommentsCountToEvents < ActiveRecord::Migration
+class AddCommentsCountToEvents < ActiveRecord::Migration[4.2]
   def change
     add_column :events, :comments_count, :integer, default: 0, null: false
 
diff --git a/db/migrate/20170108053041_add_default_to_revision_in_conference.rb b/db/migrate/20170108053041_add_default_to_revision_in_conference.rb
index 1e06838c..66517402 100644
--- a/db/migrate/20170108053041_add_default_to_revision_in_conference.rb
+++ b/db/migrate/20170108053041_add_default_to_revision_in_conference.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddDefaultToRevisionInConference < ActiveRecord::Migration
+class AddDefaultToRevisionInConference < ActiveRecord::Migration[4.2]
   def change
     change_column :conferences, :revision, :integer, default: 0, null: false
   end
diff --git a/db/migrate/20170212145523_add_enabled_to_event_schedules.rb b/db/migrate/20170212145523_add_enabled_to_event_schedules.rb
index 9d9cb819..e4255dfd 100644
--- a/db/migrate/20170212145523_add_enabled_to_event_schedules.rb
+++ b/db/migrate/20170212145523_add_enabled_to_event_schedules.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddEnabledToEventSchedules < ActiveRecord::Migration
+class AddEnabledToEventSchedules < ActiveRecord::Migration[5.0]
   def change
     add_column :event_schedules, :enabled, :boolean, default: true
   end
diff --git a/db/migrate/20170516190048_create_booths.rb b/db/migrate/20170516190048_create_booths.rb
index 4c315511..944fd30a 100644
--- a/db/migrate/20170516190048_create_booths.rb
+++ b/db/migrate/20170516190048_create_booths.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreateBooths < ActiveRecord::Migration
+class CreateBooths < ActiveRecord::Migration[4.2]
   def change
     create_table :booths do |t|
       t.string :title
diff --git a/db/migrate/20170530072155_add_type_to_cfps.rb b/db/migrate/20170530072155_add_type_to_cfps.rb
index 603a6de0..9cfae8bf 100644
--- a/db/migrate/20170530072155_add_type_to_cfps.rb
+++ b/db/migrate/20170530072155_add_type_to_cfps.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddTypeToCfps < ActiveRecord::Migration
+class AddTypeToCfps < ActiveRecord::Migration[4.2]
   class TmpCfp < ActiveRecord::Base
     self.table_name = 'cfps'
   end
diff --git a/db/migrate/20170530112510_create_booth_requests.rb b/db/migrate/20170530112510_create_booth_requests.rb
index a6358a68..a244c309 100644
--- a/db/migrate/20170530112510_create_booth_requests.rb
+++ b/db/migrate/20170530112510_create_booth_requests.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreateBoothRequests < ActiveRecord::Migration
+class CreateBoothRequests < ActiveRecord::Migration[4.2]
   def change
     create_table :booth_requests do |t|
       t.references :booth, index: true, foreign_key: true
diff --git a/db/migrate/20170603095900_create_physical_tickets.rb b/db/migrate/20170603095900_create_physical_tickets.rb
index ef8abb65..20d3c838 100644
--- a/db/migrate/20170603095900_create_physical_tickets.rb
+++ b/db/migrate/20170603095900_create_physical_tickets.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreatePhysicalTickets < ActiveRecord::Migration
+class CreatePhysicalTickets < ActiveRecord::Migration[4.2]
   def change
     create_table :physical_tickets do |t|
       t.integer :ticket_purchase_id, null: false
diff --git a/db/migrate/20170629162450_add_short_name_to_tracks.rb b/db/migrate/20170629162450_add_short_name_to_tracks.rb
index a334885f..9cb2054b 100644
--- a/db/migrate/20170629162450_add_short_name_to_tracks.rb
+++ b/db/migrate/20170629162450_add_short_name_to_tracks.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddShortNameToTracks < ActiveRecord::Migration
+class AddShortNameToTracks < ActiveRecord::Migration[4.2]
   class TmpProgram < ActiveRecord::Base
     self.table_name = 'programs'
   end
diff --git a/db/migrate/20170629232817_add_ticket_layout_to_conferences.rb b/db/migrate/20170629232817_add_ticket_layout_to_conferences.rb
index faf67332..36a1028c 100644
--- a/db/migrate/20170629232817_add_ticket_layout_to_conferences.rb
+++ b/db/migrate/20170629232817_add_ticket_layout_to_conferences.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddTicketLayoutToConferences < ActiveRecord::Migration
+class AddTicketLayoutToConferences < ActiveRecord::Migration[4.2]
   def change
     add_column :conferences, :ticket_layout, :integer, default: 0
   end
diff --git a/db/migrate/20170705075039_add_state_cfp_active_and_submitter_reference_to_tracks.rb b/db/migrate/20170705075039_add_state_cfp_active_and_submitter_reference_to_tracks.rb
index b42cf9c2..4094812b 100644
--- a/db/migrate/20170705075039_add_state_cfp_active_and_submitter_reference_to_tracks.rb
+++ b/db/migrate/20170705075039_add_state_cfp_active_and_submitter_reference_to_tracks.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddStateCfpActiveAndSubmitterReferenceToTracks < ActiveRecord::Migration
+class AddStateCfpActiveAndSubmitterReferenceToTracks < ActiveRecord::Migration[4.2]
   def change
     add_column :tracks, :state, :string
     add_column :tracks, :cfp_active, :boolean
diff --git a/db/migrate/20170711102511_create_ticket_scannings.rb b/db/migrate/20170711102511_create_ticket_scannings.rb
index 12c20eb1..bbf35e3c 100644
--- a/db/migrate/20170711102511_create_ticket_scannings.rb
+++ b/db/migrate/20170711102511_create_ticket_scannings.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreateTicketScannings < ActiveRecord::Migration
+class CreateTicketScannings < ActiveRecord::Migration[4.2]
   def change
     create_table :ticket_scannings do |t|
       t.integer :physical_ticket_id, null: false
diff --git a/db/migrate/20170712120556_add_room_and_dates_to_tracks.rb b/db/migrate/20170712120556_add_room_and_dates_to_tracks.rb
index 6c2d92b9..6cd0228c 100644
--- a/db/migrate/20170712120556_add_room_and_dates_to_tracks.rb
+++ b/db/migrate/20170712120556_add_room_and_dates_to_tracks.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddRoomAndDatesToTracks < ActiveRecord::Migration
+class AddRoomAndDatesToTracks < ActiveRecord::Migration[4.2]
   def change
     add_reference :tracks, :room, index: true, foreign_key: true
     add_column :tracks, :start_date, :date
diff --git a/db/migrate/20170715131706_make_track_state_not_null_and_add_default_value.rb b/db/migrate/20170715131706_make_track_state_not_null_and_add_default_value.rb
index 2d8d9b2d..54c6979f 100644
--- a/db/migrate/20170715131706_make_track_state_not_null_and_add_default_value.rb
+++ b/db/migrate/20170715131706_make_track_state_not_null_and_add_default_value.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class MakeTrackStateNotNullAndAddDefaultValue < ActiveRecord::Migration
+class MakeTrackStateNotNullAndAddDefaultValue < ActiveRecord::Migration[4.2]
   class TmpTrack < ActiveRecord::Base
     self.table_name = 'tracks'
   end
diff --git a/db/migrate/20170720134353_make_track_cfp_active_not_null.rb b/db/migrate/20170720134353_make_track_cfp_active_not_null.rb
index b96d84fe..c0097532 100644
--- a/db/migrate/20170720134353_make_track_cfp_active_not_null.rb
+++ b/db/migrate/20170720134353_make_track_cfp_active_not_null.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class MakeTrackCfpActiveNotNull < ActiveRecord::Migration
+class MakeTrackCfpActiveNotNull < ActiveRecord::Migration[4.2]
   class TmpTrack < ActiveRecord::Base
     self.table_name = 'tracks'
   end
diff --git a/db/migrate/20170721001700_add_index_to_physical_tickets.rb b/db/migrate/20170721001700_add_index_to_physical_tickets.rb
index 042430fe..08a436e6 100644
--- a/db/migrate/20170721001700_add_index_to_physical_tickets.rb
+++ b/db/migrate/20170721001700_add_index_to_physical_tickets.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddIndexToPhysicalTickets < ActiveRecord::Migration
+class AddIndexToPhysicalTickets < ActiveRecord::Migration[4.2]
   def change
     add_column :physical_tickets, :token, :string
     add_index :physical_tickets, :token, unique: true
diff --git a/db/migrate/20170721184810_add_custom_domain_to_conferences.rb b/db/migrate/20170721184810_add_custom_domain_to_conferences.rb
index a3e2897b..664bfbbe 100644
--- a/db/migrate/20170721184810_add_custom_domain_to_conferences.rb
+++ b/db/migrate/20170721184810_add_custom_domain_to_conferences.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddCustomDomainToConferences < ActiveRecord::Migration
+class AddCustomDomainToConferences < ActiveRecord::Migration[4.2]
   def change
     add_column :conferences, :custom_domain, :string
   end
diff --git a/db/migrate/20170726065629_add_relevance_to_tracks.rb b/db/migrate/20170726065629_add_relevance_to_tracks.rb
index 7db35227..21f2d17c 100644
--- a/db/migrate/20170726065629_add_relevance_to_tracks.rb
+++ b/db/migrate/20170726065629_add_relevance_to_tracks.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddRelevanceToTracks < ActiveRecord::Migration
+class AddRelevanceToTracks < ActiveRecord::Migration[4.2]
   def change
     add_column :tracks, :relevance, :text
   end
diff --git a/db/migrate/20170727081731_add_include_booths_to_splashpages.rb b/db/migrate/20170727081731_add_include_booths_to_splashpages.rb
index ea5882c1..350e1851 100644
--- a/db/migrate/20170727081731_add_include_booths_to_splashpages.rb
+++ b/db/migrate/20170727081731_add_include_booths_to_splashpages.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddIncludeBoothsToSplashpages < ActiveRecord::Migration
+class AddIncludeBoothsToSplashpages < ActiveRecord::Migration[4.2]
   def change
     add_column :splashpages, :include_booths, :boolean
   end
diff --git a/db/migrate/20170728182033_add_booth_limit_to_conferences.rb b/db/migrate/20170728182033_add_booth_limit_to_conferences.rb
index ae0f1410..1176375e 100644
--- a/db/migrate/20170728182033_add_booth_limit_to_conferences.rb
+++ b/db/migrate/20170728182033_add_booth_limit_to_conferences.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddBoothLimitToConferences < ActiveRecord::Migration
+class AddBoothLimitToConferences < ActiveRecord::Migration[4.2]
   def change
     add_column :conferences, :booth_limit, :integer, default: 0
   end
diff --git a/db/migrate/20170731161207_add_booths_to_email_settings.rb b/db/migrate/20170731161207_add_booths_to_email_settings.rb
index 5df76759..422006ca 100644
--- a/db/migrate/20170731161207_add_booths_to_email_settings.rb
+++ b/db/migrate/20170731161207_add_booths_to_email_settings.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddBoothsToEmailSettings < ActiveRecord::Migration
+class AddBoothsToEmailSettings < ActiveRecord::Migration[4.2]
   def change
     add_column :email_settings, :send_on_booths_acceptance, :boolean, default: false
     add_column :email_settings, :booths_acceptance_subject, :string
diff --git a/db/migrate/20170807092805_add_registration_ticket_to_tickets.rb b/db/migrate/20170807092805_add_registration_ticket_to_tickets.rb
index c2e4fd8e..d3ce8184 100644
--- a/db/migrate/20170807092805_add_registration_ticket_to_tickets.rb
+++ b/db/migrate/20170807092805_add_registration_ticket_to_tickets.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddRegistrationTicketToTickets < ActiveRecord::Migration
+class AddRegistrationTicketToTickets < ActiveRecord::Migration[4.2]
   def change
     add_column :tickets, :registration_ticket, :boolean, default: false
   end
diff --git a/db/migrate/20170809120927_add_track_reference_to_schedule.rb b/db/migrate/20170809120927_add_track_reference_to_schedule.rb
index b98fca24..9a6a0ecc 100644
--- a/db/migrate/20170809120927_add_track_reference_to_schedule.rb
+++ b/db/migrate/20170809120927_add_track_reference_to_schedule.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddTrackReferenceToSchedule < ActiveRecord::Migration
+class AddTrackReferenceToSchedule < ActiveRecord::Migration[4.2]
   def change
     add_reference :schedules, :track, index: true, foreign_key: true
   end
diff --git a/db/migrate/20170814174637_add_selected_schedule_to_tracks.rb b/db/migrate/20170814174637_add_selected_schedule_to_tracks.rb
index bedc96c3..55ad57b3 100644
--- a/db/migrate/20170814174637_add_selected_schedule_to_tracks.rb
+++ b/db/migrate/20170814174637_add_selected_schedule_to_tracks.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddSelectedScheduleToTracks < ActiveRecord::Migration
+class AddSelectedScheduleToTracks < ActiveRecord::Migration[4.2]
   def change
     add_column :tracks, :selected_schedule_id, :integer
     add_index :tracks, :selected_schedule_id
diff --git a/db/migrate/20170905110034_add_description_to_cfps.rb b/db/migrate/20170905110034_add_description_to_cfps.rb
index 968a907c..a058a1e1 100644
--- a/db/migrate/20170905110034_add_description_to_cfps.rb
+++ b/db/migrate/20170905110034_add_description_to_cfps.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddDescriptionToCfps < ActiveRecord::Migration
+class AddDescriptionToCfps < ActiveRecord::Migration[4.2]
   def change
     add_column :cfps, :description, :text
   end
diff --git a/db/migrate/20170924190528_add_amount_paid_to_ticket_purchases.rb b/db/migrate/20170924190528_add_amount_paid_to_ticket_purchases.rb
index f3357ee3..7ada30a4 100644
--- a/db/migrate/20170924190528_add_amount_paid_to_ticket_purchases.rb
+++ b/db/migrate/20170924190528_add_amount_paid_to_ticket_purchases.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddAmountPaidToTicketPurchases < ActiveRecord::Migration
+class AddAmountPaidToTicketPurchases < ActiveRecord::Migration[4.2]
   def change
     add_column :ticket_purchases, :amount_paid, :float, default: 0
   end
diff --git a/db/migrate/20171130172334_rebuild_conference_pictures.rb b/db/migrate/20171130172334_rebuild_conference_pictures.rb
index c19ae041..66973433 100644
--- a/db/migrate/20171130172334_rebuild_conference_pictures.rb
+++ b/db/migrate/20171130172334_rebuild_conference_pictures.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class RebuildConferencePictures < ActiveRecord::Migration
+class RebuildConferencePictures < ActiveRecord::Migration[5.0]
   def up
     Conference.all.each do |conference|
       conference.picture.recreate_versions!
diff --git a/db/migrate/20171201163628_add_mastodon_to_contact.rb b/db/migrate/20171201163628_add_mastodon_to_contact.rb
index a3cc50b6..4ed4d8ff 100644
--- a/db/migrate/20171201163628_add_mastodon_to_contact.rb
+++ b/db/migrate/20171201163628_add_mastodon_to_contact.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddMastodonToContact < ActiveRecord::Migration
+class AddMastodonToContact < ActiveRecord::Migration[5.0]
   def change
     add_column :contacts, :mastodon, :string
   end