SPAlert.Filter not working

Can anybody help with SPAlert filters on Sharepoint 2013?

If I set Filter property on SPAlert instance  the alert has not been sent.

SPAlert newAlert = user.Alerts.Add();

SPAlertTemplateCollection alertTemplates = new SPAlertTemplateCollection(
(SPWebService)(SPContext.Current.Site.WebApplication.Parent));

newAlert.AlertType = SPAlertType.List;
newAlert.List = list;
newAlert.Title = alertTitle;
newAlert.DeliveryChannels = SPAlertDeliveryChannels.Email;
newAlert.EventType = eventType;
newAlert.AlertFrequency = SPAlertFrequency.Immediate;
newAlert.AlertTemplate = alertTemplates[Constants.AlertTemplates.GenericListCustom];
								
var wsm = new WorkflowServicesManager(web);
var wss = wsm.GetWorkflowSubscriptionService();
var subscriptions = wss.EnumerateSubscriptionsByList(list.ID);
bool assotiationExist = false;
var guid = Constants.Workflows.ApprovalWF.Guid;
foreach (var subs in subscriptions)
{
	assotiationExist = subs.DefinitionId == guid;
        if (assotiationExist)
        {
               newAlert.Filter = "<Query><Eq><FieldRef Name=\"ApprovalStatus\"/><Value type=\"string\">Approved</Value></Eq></Query>";
        }
}

newAlert.Update(false);