2706 again

Author: p

spec/integration/crud_spec.rb

@@ -157,6 +157,9 @@
     context 'with read preference specified on operation level' do
       require_topology :sharded
 
+      # RUBY-2706
+      min_server_fcv '3.6'
+
       it 'passes the read preference' do
         event = Utils.get_command_event(client, 'explain') do |client|
           client['foo'].find({}, read: {mode: :secondary_preferred}).explain.should be_explain_output