diff --git a/lib/data/models/client_model.dart b/lib/data/models/client_model.dart
index fca2b02b6..e698380c1 100644
--- a/lib/data/models/client_model.dart
+++ b/lib/data/models/client_model.dart
@@ -6,6 +6,7 @@ import 'package:built_collection/built_collection.dart';
 import 'package:built_value/built_value.dart';
 import 'package:built_value/serializer.dart';
 import 'package:collection/collection.dart';
+import 'package:diacritic/diacritic.dart';
 
 // Project imports:
 import 'package:invoiceninja_flutter/constants.dart';
@@ -385,14 +386,15 @@ abstract class ClientEntity extends Object
 
     switch (sortField) {
       case ClientFields.name:
-        response = clientA.displayName
+        response = removeDiacritics(clientA.displayName)
             .toLowerCase()
-            .compareTo(clientB.displayName.toLowerCase());
+            .compareTo(removeDiacritics(clientB.displayName).toLowerCase());
         break;
       case ClientFields.contactName:
-        response = clientA.primaryContact.fullName
+        response = removeDiacritics(clientA.primaryContact.fullName)
             .toLowerCase()
-            .compareTo(clientB.primaryContact.fullName.toLowerCase());
+            .compareTo(removeDiacritics(clientB.primaryContact.fullName)
+                .toLowerCase());
         break;
       case ClientFields.contactEmail:
         response = clientA.primaryContact.email
diff --git a/lib/data/models/expense_model.dart b/lib/data/models/expense_model.dart
index 321c64ba7..e3c89df85 100644
--- a/lib/data/models/expense_model.dart
+++ b/lib/data/models/expense_model.dart
@@ -3,6 +3,7 @@ import 'package:built_collection/built_collection.dart';
 import 'package:built_value/built_value.dart';
 import 'package:built_value/serializer.dart';
 import 'package:collection/collection.dart';
+import 'package:diacritic/diacritic.dart';
 
 // Project imports:
 import 'package:invoiceninja_flutter/constants.dart';
@@ -412,17 +413,17 @@ abstract class ExpenseEntity extends Object
       case ExpenseFields.client:
         final clientA = clientMap[expenseA.clientId] ?? ClientEntity();
         final clientB = clientMap[expenseB.clientId] ?? ClientEntity();
-        response = clientA.listDisplayName
+        response = removeDiacritics(clientA.listDisplayName)
             .toLowerCase()
-            .compareTo(clientB.listDisplayName.toLowerCase());
+            .compareTo(removeDiacritics(clientB.listDisplayName).toLowerCase());
         break;
       case ExpenseFields.vendorId:
       case ExpenseFields.vendor:
         final vendorA = vendorMap[expenseA.vendorId] ?? VendorEntity();
         final vendorB = vendorMap[expenseB.vendorId] ?? VendorEntity();
-        response = vendorA.listDisplayName
+        response = removeDiacritics(vendorA.listDisplayName)
             .toLowerCase()
-            .compareTo(vendorB.listDisplayName.toLowerCase());
+            .compareTo(removeDiacritics(vendorB.listDisplayName).toLowerCase());
         break;
       case EntityFields.state:
         final stateA =
diff --git a/lib/data/models/invoice_model.dart b/lib/data/models/invoice_model.dart
index e11943395..af6671a91 100644
--- a/lib/data/models/invoice_model.dart
+++ b/lib/data/models/invoice_model.dart
@@ -3,6 +3,7 @@ import 'package:built_collection/built_collection.dart';
 import 'package:built_value/built_value.dart';
 import 'package:built_value/serializer.dart';
 import 'package:collection/collection.dart';
+import 'package:diacritic/diacritic.dart';
 
 // Project imports:
 import 'package:invoiceninja_flutter/constants.dart';
@@ -609,8 +610,10 @@ abstract class InvoiceEntity extends Object
     final InvoiceEntity invoiceB = sortAscending ? invoice : this;
     switch (sortField) {
       case InvoiceFields.number:
-        var invoiceANumber = invoiceA.number ?? '';
-        var invoiceBNumber = invoiceB.number ?? '';
+        var invoiceANumber =
+            (invoiceA.number ?? '').isEmpty ? 'ZZZZZZZZZZ' : invoiceA.number;
+        var invoiceBNumber =
+            (invoiceB.number ?? '').isEmpty ? 'ZZZZZZZZZZ' : invoiceB.number;
         invoiceANumber = recurringPrefix.isNotEmpty &&
                 //(invoiceA.recurringId ?? '').isNotEmpty &&
                 invoiceANumber.startsWith(recurringPrefix)
@@ -734,9 +737,9 @@ abstract class InvoiceEntity extends Object
       case InvoiceFields.client:
         final clientA = clientMap[invoiceA.clientId] ?? ClientEntity();
         final clientB = clientMap[invoiceB.clientId] ?? ClientEntity();
-        response = clientA.listDisplayName
+        response = removeDiacritics(clientA.listDisplayName)
             .toLowerCase()
-            .compareTo(clientB.listDisplayName.toLowerCase());
+            .compareTo(removeDiacritics(clientB.listDisplayName).toLowerCase());
         break;
       case InvoiceFields.isViewed:
         response = invoiceB.isViewed ? 1 : -1;
diff --git a/lib/data/models/project_model.dart b/lib/data/models/project_model.dart
index eed0399e0..c69845e65 100644
--- a/lib/data/models/project_model.dart
+++ b/lib/data/models/project_model.dart
@@ -2,6 +2,7 @@
 import 'package:built_collection/built_collection.dart';
 import 'package:built_value/built_value.dart';
 import 'package:built_value/serializer.dart';
+import 'package:diacritic/diacritic.dart';
 
 // Project imports:
 import 'package:invoiceninja_flutter/data/models/entities.dart';
@@ -220,9 +221,9 @@ abstract class ProjectEntity extends Object
       case ProjectFields.client:
         final clientA = clientMap[projectA.clientId] ?? ClientEntity();
         final clientB = clientMap[projectB.clientId] ?? ClientEntity();
-        response = clientA.listDisplayName
+        response = removeDiacritics(clientA.listDisplayName)
             .toLowerCase()
-            .compareTo(clientB.listDisplayName.toLowerCase());
+            .compareTo(removeDiacritics(clientB.listDisplayName).toLowerCase());
         break;
       case ProjectFields.clientNumber:
         final clientA = clientMap[projectA.clientId] ?? ClientEntity();
diff --git a/lib/data/models/task_model.dart b/lib/data/models/task_model.dart
index e2be44020..3f86ebeda 100644
--- a/lib/data/models/task_model.dart
+++ b/lib/data/models/task_model.dart
@@ -6,6 +6,7 @@ import 'package:built_collection/built_collection.dart';
 import 'package:built_value/built_value.dart';
 import 'package:built_value/serializer.dart';
 import 'package:collection/collection.dart';
+import 'package:diacritic/diacritic.dart';
 
 // Project imports:
 import 'package:invoiceninja_flutter/constants.dart';
@@ -629,9 +630,9 @@ abstract class TaskEntity extends Object
       case TaskFields.client:
         final clientA = clientMap[taskA.clientId] ?? ClientEntity();
         final clientB = clientMap[taskB.clientId] ?? ClientEntity();
-        response = clientA.listDisplayName
+        response = removeDiacritics(clientA.listDisplayName)
             .toLowerCase()
-            .compareTo(clientB.listDisplayName.toLowerCase());
+            .compareTo(removeDiacritics(clientB.listDisplayName).toLowerCase());
         break;
       case TaskFields.projectId:
       case TaskFields.project:
diff --git a/lib/data/models/vendor_model.dart b/lib/data/models/vendor_model.dart
index abbefdaf9..611c95d23 100644
--- a/lib/data/models/vendor_model.dart
+++ b/lib/data/models/vendor_model.dart
@@ -3,6 +3,7 @@ import 'package:built_collection/built_collection.dart';
 import 'package:built_value/built_value.dart';
 import 'package:built_value/serializer.dart';
 import 'package:collection/collection.dart';
+import 'package:diacritic/diacritic.dart';
 
 // Project imports:
 import 'package:invoiceninja_flutter/data/models/entities.dart';
@@ -223,8 +224,9 @@ abstract class VendorEntity extends Object
 
     switch (sortField) {
       case VendorFields.name:
-        response =
-            vendorA.name.toLowerCase().compareTo(vendorB.name.toLowerCase());
+        response = removeDiacritics(vendorA.name)
+            .toLowerCase()
+            .compareTo(removeDiacritics(vendorB.name).toLowerCase());
         break;
       case VendorFields.city:
         response =
diff --git a/pubspec.foss.yaml b/pubspec.foss.yaml
index ef9de2205..a7279c037 100644
--- a/pubspec.foss.yaml
+++ b/pubspec.foss.yaml
@@ -57,6 +57,7 @@ dependencies:
   pointer_interceptor: ^0.9.0
   contacts_service: ^0.6.1
   super_editor: ^0.1.0
+  diacritic: ^0.1.3
   # quick_actions: ^0.2.1
   # idb_shim: ^1.11.1+1
 
diff --git a/pubspec.lock b/pubspec.lock
index 433cd170f..eb3596028 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -274,6 +274,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.0"
+  diacritic:
+    dependency: "direct main"
+    description:
+      name: diacritic
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.1.3"
   extension:
     dependency: transitive
     description:
diff --git a/pubspec.next.yaml b/pubspec.next.yaml
index 53a66eb55..5977c50f2 100644
--- a/pubspec.next.yaml
+++ b/pubspec.next.yaml
@@ -57,6 +57,7 @@ dependencies:
   pointer_interceptor: ^0.9.0
   contacts_service: ^0.6.1
   super_editor: ^0.1.0
+  diacritic: ^0.1.3
   # quick_actions: ^0.2.1
   # idb_shim: ^1.11.1+1
 
diff --git a/pubspec.yaml b/pubspec.yaml
index 53a66eb55..5977c50f2 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -57,6 +57,7 @@ dependencies:
   pointer_interceptor: ^0.9.0
   contacts_service: ^0.6.1
   super_editor: ^0.1.0
+  diacritic: ^0.1.3
   # quick_actions: ^0.2.1
   # idb_shim: ^1.11.1+1