diff --git a/d2-tracker/dhis2.angular.services.js b/d2-tracker/dhis2.angular.services.js
index a7e363e9a..69c01fe56 100644
--- a/d2-tracker/dhis2.angular.services.js
+++ b/d2-tracker/dhis2.angular.services.js
@@ -1779,21 +1779,21 @@ var d2Services = angular.module('d2Services', ['ngResource'])
             variables = pushVariable(variables, 'environment', 'WebClient',null,'TEXT',true,'V','',false);
             variables = pushVariable(variables, 'current_date', DateUtils.getToday(), null, 'DATE', true, 'V', '', false );
 
-            variables = pushVariable(variables, 'event_date', executingEvent.eventDate, null, 'DATE', true, 'V', '', false );
-            variables = pushVariable(variables, 'due_date', executingEvent.dueDate, null, 'DATE', true, 'V', '' );
+            variables = pushVariable(variables, 'event_date', executingEvent.eventDate, null, 'DATE', !!executingEvent.eventDate, 'V', '', false );
+            variables = pushVariable(variables, 'due_date', executingEvent.dueDate, null, 'DATE', !!executingEvent.dueDate, 'V', '' );
             variables = pushVariable(variables, 'event_count', evs ? evs.all.length : 0, null, 'INTEGER', true, 'V', '', false );
 
-            variables = pushVariable(variables, 'enrollment_date', selectedEnrollment ? selectedEnrollment.enrollmentDate : '', null, 'DATE', selectedEnrollment ? selectedEnrollment.enrollmentDate ? true : false : false, 'V', '', false );
-            variables = pushVariable(variables, 'enrollment_id', selectedEnrollment ? selectedEnrollment.enrollment : '', null, 'TEXT',  selectedEnrollment ? true : false, 'V', '', false );
-            variables = pushVariable(variables, 'event_id', executingEvent ? executingEvent.event : '', null, 'TEXT',  executingEvent ? true : false, 'V', executingEvent ? executingEvent.eventDate : false, false);
-            variables = pushVariable(variables, 'event_status', executingEvent ? executingEvent.status : '', null, 'TEXT',  executingEvent ? true : false, 'V', executingEvent ? executingEvent.eventDate : false, false);
+            variables = pushVariable(variables, 'enrollment_date', selectedEnrollment ? selectedEnrollment.enrollmentDate : '', null, 'DATE', !!(selectedEnrollment && selectedEnrollment.enrollmentDate), 'V', '', false );
+            variables = pushVariable(variables, 'enrollment_id', selectedEnrollment ? selectedEnrollment.enrollment : '', null, 'TEXT',  !!selectedEnrollment, 'V', '', false );
+            variables = pushVariable(variables, 'event_id', executingEvent ? executingEvent.event : '', null, 'TEXT', !!executingEvent, 'V', executingEvent ? executingEvent.eventDate : false, false);
+            variables = pushVariable(variables, 'event_status', executingEvent ? executingEvent.status : '', null, 'TEXT', !!executingEvent, 'V', executingEvent ? executingEvent.eventDate : false, false);
 
-            variables = pushVariable(variables, 'incident_date', selectedEnrollment ? selectedEnrollment.incidentDate : '', null, 'DATE',  selectedEnrollment ? true : false, 'V', '', false);
+            variables = pushVariable(variables, 'incident_date', selectedEnrollment ? selectedEnrollment.incidentDate : '', null, 'DATE', !!selectedEnrollment, 'V', '', false);
             variables = pushVariable(variables, 'enrollment_count', selectedEnrollment ? 1 : 0, null, 'INTEGER', true, 'V', '', false);
             variables = pushVariable(variables, 'tei_count', selectedEnrollment ? 1 : 0, null, 'INTEGER', true, 'V', '', false);
             
-            variables = pushVariable(variables, 'program_stage_id',(selectedProgramStage && selectedProgramStage.id) || '', null, 'TEXT', selectedProgramStage && selectedProgramStage.id ? true : false, 'V', '', false);
-            variables = pushVariable(variables, 'program_stage_name',(selectedProgramStage && selectedProgramStage.name) || '', null, 'TEXT', selectedProgramStage && selectedProgramStage.name ? true : false, 'V', '', false);
+            variables = pushVariable(variables, 'program_stage_id',(selectedProgramStage && selectedProgramStage.id) || '', null, 'TEXT', !!(selectedProgramStage && selectedProgramStage.id), 'V', '', false);
+            variables = pushVariable(variables, 'program_stage_name',(selectedProgramStage && selectedProgramStage.name) || '', null, 'TEXT', !!(selectedProgramStage && selectedProgramStage.name), 'V', '', false);
 
 
             //Push all constant values:
@@ -1802,7 +1802,7 @@ var d2Services = angular.module('d2Services', ['ngResource'])
             });
 
             if(selectedOrgUnit){
-                variables = pushVariable(variables, 'orgunit_code', selectedOrgUnit.code, null, 'TEXT', selectedOrgUnit.code ? true : false, 'V', '', false);
+                variables = pushVariable(variables, 'orgunit_code', selectedOrgUnit.code, null, 'TEXT', !!selectedOrgUnit.code, 'V', '', false);
             }
 
             return variables;
@@ -2646,12 +2646,7 @@ var d2Services = angular.module('d2Services', ['ngResource'])
         },
         "d2:concatenate": {
             execute: function(parameters) {
-                var returnString = "'";
-                for (var i = 0; i < parameters.length; i++) {
-                    returnString += parameters[i];
-                }
-                returnString += "'";
-                return returnString;
+                return parameters.join('');
             },
         },
         "d2:addDays": {
@@ -2659,9 +2654,7 @@ var d2Services = angular.module('d2Services', ['ngResource'])
             execute: function(parameters) {
                 var date = $filter('trimquotes')(parameters[0]);
                 var daystoadd = $filter('trimquotes')(parameters[1]);
-                var newdate = DateUtils.format( moment(date, CalendarService.getSetting().momentFormat).add(daystoadd, 'days') );
-                var newdatestring = "'" + newdate + "'";
-                return newdatestring
+                return DateUtils.format( moment(date, CalendarService.getSetting().momentFormat).add(daystoadd, 'days') );
             },
         },
         "d2:zing": {
@@ -2822,7 +2815,7 @@ var d2Services = angular.module('d2Services', ['ngResource'])
             execute: function(parameters, variablesHash) {
                 var variableName = parameters[0];
                 var variableObject = variablesHash[variableName];
-                var valueFound = "''";
+                var valueFound = "";
                 if(variableObject)
                 {
                     if(variableObject.variableEventDate){
@@ -2937,7 +2930,7 @@ var d2Services = angular.module('d2Services', ['ngResource'])
                 var startChar = string.length < parameters[1] - 1 ? -1 : parameters[1];
                 var endChar = string.length < parameters[2] ? -1 : parameters[2];
                 if(startChar < 0 || endChar < 0) {
-                    return "''";
+                    return "";
                 }
                 var returnString =  string.substring(startChar, endChar);
                 returnString = VariableService.processValue(returnString, 'TEXT');
@@ -3138,7 +3131,7 @@ var d2Services = angular.module('d2Services', ['ngResource'])
                 accExpression += 'false';
             } else {
                 const dhisFunctionResult = dhisFunction.execute(evaluatedArguments, variablesHash, selectedOrgUnit);
-                accExpression += dhisFunctionResult;
+                accExpression += getInjectionValue(dhisFunctionResult);
             }
 
             return {