Don't update milestones on boards if the feature is not available

app/services/boards/update_service.rb

 module Boards
   class UpdateService < BaseService
     def execute(board)
-      board.update(name: params[:name], milestone_id: params[:milestone_id])
+      params.delete(:milestone_id) unless project.feature_available?(:issue_board_milestone)
+
+      board.update(params)
     end
   end
 end

spec/services/boards/update_service_spec.rb

@@ -24,5 +24,25 @@ describe Boards::UpdateService, services: true do
 
       expect(service.execute(board)).to eq false
     end
+
+    it 'udpates the milestone with issue board milestones enabled' do
+      stub_licensed_features(issue_board_milestone: true)
+      milestone = create(:milestone, project: project)
+
+      service = described_class.new(project, double, milestone_id: milestone.id)
+      service.execute(board)
+
+      expect(board.reload.milestone).to eq(milestone)
+    end
+
+    it 'udpates the milestone with the issue board milestones feature enabled' do
+      stub_licensed_features(issue_board_milestone: false)
+      milestone = create(:milestone, project: project)
+
+      service = described_class.new(project, double, milestone_id: milestone.id)
+      service.execute(board)
+
+      expect(board.reload.milestone).to be_nil
+    end
   end
 end