James Lopez
--- a/lib/gitlab/import_export/relation_factory.rb
+++ b/lib/gitlab/import_export/relation_factory.rb
+            unless events.blank?
+              existing_object.assign_attributes(events: events)
+            end
+
            existing_object
          else
            relation_class.new(parsed_relation_hash)
          end
        end
      end
+
+      def existing_object
+        @existing_object ||=
+          begin
+            finder_hash = parsed_relation_hash.slice(*FINDER_ATTRIBUTES)
+            existing_object = relation_class.find_or_create_by(finder_hash)
--- a/lib/gitlab/import_export/version_checker.rb
+++ b/lib/gitlab/import_export/version_checker.rb
      end

      def verify_version!(version)
-        if Gem::Version.new(version) > Gem::Version.new(Gitlab::ImportExport.version)
-          raise Gitlab::ImportExport::Error.new("Import version mismatch: Required <= #{Gitlab::ImportExport.version} but was #{version}")
+        if Gem::Version.new(version) != Gem::Version.new(Gitlab::ImportExport.version)
--- a/lib/gitlab/import_export/relation_factory.rb
+++ b/lib/gitlab/import_export/relation_factory.rb
+            end
+
            existing_object
          else
            relation_class.new(parsed_relation_hash)
          end
        end
      end
+
+      def existing_object
+        @existing_object ||=
+          begin
+            finder_hash = parsed_relation_hash.slice(*FINDER_ATTRIBUTES)
+            existing_object = relation_class.find_or_create_by(finder_hash)
+            # Done in two steps, as MySQL behaves differently than PostgreSQL using
+            # the +find_or_create_by+ method and does not return the ID the second time.