RocketChat.Migrations.add({ version: 71, up() { //Removes the reactions on messages which are the system type "rm" ;) RocketChat.models.Messages.find({ 't': 'rm', 'reactions': { $exists: true, $not: {$size: 0} } }, { t: 1 }).forEach(function(message) { RocketChat.models.Messages.update({ _id: message._id }, { $set: { reactions: [] }}); }); } });