diff --git a/lib/data/models/invoice_model.dart b/lib/data/models/invoice_model.dart
index 50d63f8e1..35ba71b9b 100644
--- a/lib/data/models/invoice_model.dart
+++ b/lib/data/models/invoice_model.dart
@@ -318,9 +318,8 @@ abstract class InvoiceEntity extends Object
         ..documents.clear()
         ..lineItems.replace(lineItems
             .where((lineItem) =>
-                lineItem!.typeId != InvoiceItemEntity.TYPE_UNPAID_FEE)
-            .map((lineItem) => lineItem!
-                .rebuild((b) => b..typeId = InvoiceItemEntity.TYPE_STANDARD))
+                lineItem.typeId != InvoiceItemEntity.TYPE_UNPAID_FEE)
+            .map((lineItem) => lineItem.rebuild((b) => b..typeId = InvoiceItemEntity.TYPE_STANDARD))
             .toList())
         ..invitations.replace(
           invitations
@@ -561,7 +560,7 @@ abstract class InvoiceEntity extends Object
 
   @override
   @BuiltValueField(wireName: 'line_items')
-  BuiltList<InvoiceItemEntity?> get lineItems;
+  BuiltList<InvoiceItemEntity> get lineItems;
 
   BuiltList<InvitationEntity> get invitations;
 
@@ -645,11 +644,11 @@ abstract class InvoiceEntity extends Object
         kMillisecondsToRefreshActivities;
   }
 
-  bool get hasTasks => lineItems.any((item) => item!.isTask);
+  bool get hasTasks => lineItems.any((item) => item.isTask);
 
-  bool get hasProducts => lineItems.any((item) => !item!.isTask);
+  bool get hasProducts => lineItems.any((item) => !item.isTask);
 
-  bool get hasExpenses => lineItems.any((item) => item!.isExpense);
+  bool get hasExpenses => lineItems.any((item) => item.isExpense);
 
   @override
   bool get isEditable {
@@ -915,7 +914,7 @@ abstract class InvoiceEntity extends Object
   @override
   bool matchesFilter(String? filter) {
     for (var i = 0; i < lineItems.length; i++) {
-      final lineItem = lineItems[i]!;
+      final lineItem = lineItems[i];
       final isMatch = matchesStrings(
         haystacks: [
           lineItem.productKey,
@@ -1409,7 +1408,7 @@ abstract class InvoiceEntity extends Object
     }
 
     for (final item in lineItems) {
-      final itemTaxable = getItemTaxable(item!, amount, precision);
+      final itemTaxable = getItemTaxable(item, amount, precision);
 
       if (item.taxName1.isNotEmpty) {
         final itemTaxAmount = calculateAmount(itemTaxable, item.taxRate1);
diff --git a/lib/data/models/invoice_model.g.dart b/lib/data/models/invoice_model.g.dart
index 18993699b..fd0daea83 100644
--- a/lib/data/models/invoice_model.g.dart
+++ b/lib/data/models/invoice_model.g.dart
@@ -269,7 +269,7 @@ class _$InvoiceEntitySerializer implements StructuredSerializer<InvoiceEntity> {
       'line_items',
       serializers.serialize(object.lineItems,
           specifiedType: const FullType(
-              BuiltList, const [const FullType.nullable(InvoiceItemEntity)])),
+              BuiltList, const [const FullType(InvoiceItemEntity)])),
       'invitations',
       serializers.serialize(object.invitations,
           specifiedType: const FullType(
@@ -689,9 +689,9 @@ class _$InvoiceEntitySerializer implements StructuredSerializer<InvoiceEntity> {
           break;
         case 'line_items':
           result.lineItems.replace(serializers.deserialize(value,
-              specifiedType: const FullType(BuiltList, const [
-                const FullType.nullable(InvoiceItemEntity)
-              ]))! as BuiltList<Object?>);
+                  specifiedType: const FullType(
+                      BuiltList, const [const FullType(InvoiceItemEntity)]))!
+              as BuiltList<Object?>);
           break;
         case 'invitations':
           result.invitations.replace(serializers.deserialize(value,
@@ -1571,7 +1571,7 @@ class _$InvoiceEntity extends InvoiceEntity {
   @override
   final BuiltList<InvoiceScheduleEntity>? recurringDates;
   @override
-  final BuiltList<InvoiceItemEntity?> lineItems;
+  final BuiltList<InvoiceItemEntity> lineItems;
   @override
   final BuiltList<InvitationEntity> invitations;
   @override
@@ -2313,10 +2313,10 @@ class InvoiceEntityBuilder
   set recurringDates(ListBuilder<InvoiceScheduleEntity>? recurringDates) =>
       _$this._recurringDates = recurringDates;
 
-  ListBuilder<InvoiceItemEntity?>? _lineItems;
-  ListBuilder<InvoiceItemEntity?> get lineItems =>
-      _$this._lineItems ??= new ListBuilder<InvoiceItemEntity?>();
-  set lineItems(ListBuilder<InvoiceItemEntity?>? lineItems) =>
+  ListBuilder<InvoiceItemEntity>? _lineItems;
+  ListBuilder<InvoiceItemEntity> get lineItems =>
+      _$this._lineItems ??= new ListBuilder<InvoiceItemEntity>();
+  set lineItems(ListBuilder<InvoiceItemEntity>? lineItems) =>
       _$this._lineItems = lineItems;
 
   ListBuilder<InvitationEntity>? _invitations;
diff --git a/lib/data/models/serializers.g.dart b/lib/data/models/serializers.g.dart
index 54bd4313e..1379089df 100644
--- a/lib/data/models/serializers.g.dart
+++ b/lib/data/models/serializers.g.dart
@@ -511,9 +511,8 @@ Serializers _$serializers = (new Serializers().toBuilder()
               BuiltList, const [const FullType(InvoiceScheduleEntity)]),
           () => new ListBuilder<InvoiceScheduleEntity>())
       ..addBuilderFactory(
-          const FullType(
-              BuiltList, const [const FullType.nullable(InvoiceItemEntity)]),
-          () => new ListBuilder<InvoiceItemEntity?>())
+          const FullType(BuiltList, const [const FullType(InvoiceItemEntity)]),
+          () => new ListBuilder<InvoiceItemEntity>())
       ..addBuilderFactory(
           const FullType(BuiltList, const [const FullType(InvitationEntity)]),
           () => new ListBuilder<InvitationEntity>())
diff --git a/lib/redux/credit/credit_actions.dart b/lib/redux/credit/credit_actions.dart
index a173e81b5..fee024d63 100644
--- a/lib/redux/credit/credit_actions.dart
+++ b/lib/redux/credit/credit_actions.dart
@@ -189,10 +189,13 @@ class AddCreditItems implements PersistUI {
 }
 
 class UpdateCreditItem implements PersistUI {
-  UpdateCreditItem({this.index, this.creditItem});
+  UpdateCreditItem({
+    required this.index,
+    required this.creditItem,
+  });
 
-  final int? index;
-  final InvoiceItemEntity? creditItem;
+  final int index;
+  final InvoiceItemEntity creditItem;
 }
 
 class DeleteCreditItem implements PersistUI {
diff --git a/lib/redux/credit/credit_middleware.dart b/lib/redux/credit/credit_middleware.dart
index a49348cdd..a4f562a00 100644
--- a/lib/redux/credit/credit_middleware.dart
+++ b/lib/redux/credit/credit_middleware.dart
@@ -284,7 +284,7 @@ Middleware<AppState> _saveCredit(CreditRepository repository) {
     // remove any empty line items
     final updatedCredit = action.credit.rebuild((b) => b
       ..lineItems
-          .replace(action.credit.lineItems.where((item) => !item!.isEmpty)));
+          .replace(action.credit.lineItems.where((item) => !item.isEmpty)));
 
     repository
         .saveData(store.state.credentials, updatedCredit, action.action)
diff --git a/lib/redux/credit/credit_reducer.dart b/lib/redux/credit/credit_reducer.dart
index 1784f7c3b..3985c781b 100644
--- a/lib/redux/credit/credit_reducer.dart
+++ b/lib/redux/credit/credit_reducer.dart
@@ -178,10 +178,10 @@ InvoiceEntity? _removeCreditItem(
 
 InvoiceEntity? _updateCreditItem(
     InvoiceEntity? credit, UpdateCreditItem action) {
-  if (credit!.lineItems.length <= action.index!) {
+  if (credit!.lineItems.length <= action.index) {
     return credit;
   }
-  return credit.rebuild((b) => b..lineItems[action.index!] = action.creditItem);
+  return credit.rebuild((b) => b..lineItems[action.index] = action.creditItem);
 }
 
 final creditListReducer = combineReducers<ListUIState>([
diff --git a/lib/redux/invoice/invoice_actions.dart b/lib/redux/invoice/invoice_actions.dart
index 00982bcf2..3f55569b3 100644
--- a/lib/redux/invoice/invoice_actions.dart
+++ b/lib/redux/invoice/invoice_actions.dart
@@ -193,10 +193,13 @@ class AddInvoiceItems implements PersistUI {
 }
 
 class UpdateInvoiceItem implements PersistUI {
-  UpdateInvoiceItem({this.index, this.invoiceItem});
+  UpdateInvoiceItem({
+    required this.index,
+    required this.invoiceItem,
+  });
 
-  final int? index;
-  final InvoiceItemEntity? invoiceItem;
+  final int index;
+  final InvoiceItemEntity invoiceItem;
 }
 
 class DeleteInvoiceItem implements PersistUI {
@@ -700,7 +703,8 @@ void handleInvoiceAction(BuildContext? context, List<BaseEntity?> invoices,
               title: Text(
                 invoiceIds.length == 1
                     ? localization.emailInvoice
-                    : localization.emailCountInvoices.replaceFirst(':count', '${invoiceIds.length}'),
+                    : localization.emailCountInvoices
+                        .replaceFirst(':count', '${invoiceIds.length}'),
               ),
               children: templates.keys
                   .map((template) => SimpleDialogOption(
diff --git a/lib/redux/invoice/invoice_middleware.dart b/lib/redux/invoice/invoice_middleware.dart
index 956c954b3..42b29759f 100644
--- a/lib/redux/invoice/invoice_middleware.dart
+++ b/lib/redux/invoice/invoice_middleware.dart
@@ -381,7 +381,7 @@ Middleware<AppState> _saveInvoice(InvoiceRepository repository) {
     // remove any empty line items
     final updatedInvoice = action.invoice.rebuild((b) => b
       ..lineItems
-          .replace(action.invoice.lineItems.where((item) => !item!.isEmpty)));
+          .replace(action.invoice.lineItems.where((item) => !item.isEmpty)));
 
     repository
         .saveData(
diff --git a/lib/redux/invoice/invoice_reducer.dart b/lib/redux/invoice/invoice_reducer.dart
index 79a521e52..17dfd8ff4 100644
--- a/lib/redux/invoice/invoice_reducer.dart
+++ b/lib/redux/invoice/invoice_reducer.dart
@@ -182,11 +182,11 @@ InvoiceEntity? _removeInvoiceItem(
 
 InvoiceEntity? _updateInvoiceItem(
     InvoiceEntity? invoice, UpdateInvoiceItem action) {
-  if (invoice!.lineItems.length <= action.index!) {
+  if (invoice!.lineItems.length <= action.index) {
     return invoice;
   }
   return invoice
-      .rebuild((b) => b..lineItems[action.index!] = action.invoiceItem);
+      .rebuild((b) => b..lineItems[action.index] = action.invoiceItem);
 }
 
 final invoiceListReducer = combineReducers<ListUIState>([
diff --git a/lib/redux/purchase_order/purchase_order_actions.dart b/lib/redux/purchase_order/purchase_order_actions.dart
index 7f6500b4a..83d1b63d5 100644
--- a/lib/redux/purchase_order/purchase_order_actions.dart
+++ b/lib/redux/purchase_order/purchase_order_actions.dart
@@ -488,10 +488,13 @@ class AddPurchaseOrderItems implements PersistUI {
 }
 
 class UpdatePurchaseOrderItem implements PersistUI {
-  UpdatePurchaseOrderItem({this.index, this.purchaseOrderItem});
+  UpdatePurchaseOrderItem({
+    required this.index,
+    required this.purchaseOrderItem,
+  });
 
-  final int? index;
-  final InvoiceItemEntity? purchaseOrderItem;
+  final int index;
+  final InvoiceItemEntity purchaseOrderItem;
 }
 
 class DeletePurchaseOrderItem implements PersistUI {
diff --git a/lib/redux/purchase_order/purchase_order_middleware.dart b/lib/redux/purchase_order/purchase_order_middleware.dart
index 6d02db816..8a9a619e1 100644
--- a/lib/redux/purchase_order/purchase_order_middleware.dart
+++ b/lib/redux/purchase_order/purchase_order_middleware.dart
@@ -391,7 +391,7 @@ Middleware<AppState> _savePurchaseOrder(PurchaseOrderRepository repository) {
     // remove any empty line items
     final updatedPurchaseOrder = action.purchaseOrder.rebuild((b) => b
       ..lineItems.replace(
-          action.purchaseOrder.lineItems.where((item) => !item!.isEmpty)));
+          action.purchaseOrder.lineItems.where((item) => !item.isEmpty)));
 
     repository
         .saveData(
diff --git a/lib/redux/purchase_order/purchase_order_reducer.dart b/lib/redux/purchase_order/purchase_order_reducer.dart
index 5be7725f8..11d08ce68 100644
--- a/lib/redux/purchase_order/purchase_order_reducer.dart
+++ b/lib/redux/purchase_order/purchase_order_reducer.dart
@@ -206,11 +206,11 @@ InvoiceEntity? _removePurchaseOrderItem(
 
 InvoiceEntity? _updatePurchaseOrderItem(
     InvoiceEntity? purchaseOrder, UpdatePurchaseOrderItem action) {
-  if (purchaseOrder!.lineItems.length <= action.index!) {
+  if (purchaseOrder!.lineItems.length <= action.index) {
     return purchaseOrder;
   }
   return purchaseOrder
-      .rebuild((b) => b..lineItems[action.index!] = action.purchaseOrderItem);
+      .rebuild((b) => b..lineItems[action.index] = action.purchaseOrderItem);
 }
 
 final purchaseOrderListReducer = combineReducers<ListUIState>([
diff --git a/lib/redux/quote/quote_actions.dart b/lib/redux/quote/quote_actions.dart
index bdee32f14..69882e754 100644
--- a/lib/redux/quote/quote_actions.dart
+++ b/lib/redux/quote/quote_actions.dart
@@ -190,10 +190,13 @@ class AddQuoteItems implements PersistUI {
 }
 
 class UpdateQuoteItem implements PersistUI {
-  UpdateQuoteItem({this.index, this.quoteItem});
+  UpdateQuoteItem({
+    required this.index,
+    required this.quoteItem,
+  });
 
-  final int? index;
-  final InvoiceItemEntity? quoteItem;
+  final int index;
+  final InvoiceItemEntity quoteItem;
 }
 
 class DeleteQuoteItem implements PersistUI {
@@ -553,7 +556,8 @@ Future handleQuoteAction(BuildContext context, List<BaseEntity?> quotes,
       break;
     case EntityAction.approve:
       final message = quoteIds.length > 1
-          ? localization!.approvedQuotes.replaceFirst(':value', ':count')
+          ? localization!.approvedQuotes
+              .replaceFirst(':value', ':count')
               .replaceFirst(':count', quoteIds.length.toString())
           : localization!.approveQuote;
       store.dispatch(
diff --git a/lib/redux/quote/quote_middleware.dart b/lib/redux/quote/quote_middleware.dart
index 9bffdff37..c0206ee4e 100644
--- a/lib/redux/quote/quote_middleware.dart
+++ b/lib/redux/quote/quote_middleware.dart
@@ -329,7 +329,7 @@ Middleware<AppState> _saveQuote(QuoteRepository repository) {
     // remove any empty line items
     final updatedQuote = action.quote.rebuild((b) => b
       ..lineItems
-          .replace(action.quote.lineItems.where((item) => !item!.isEmpty)));
+          .replace(action.quote.lineItems.where((item) => !item.isEmpty)));
 
     repository
         .saveData(store.state.credentials, updatedQuote, action.action)
diff --git a/lib/redux/quote/quote_reducer.dart b/lib/redux/quote/quote_reducer.dart
index e5f54dc21..c35cf38ec 100644
--- a/lib/redux/quote/quote_reducer.dart
+++ b/lib/redux/quote/quote_reducer.dart
@@ -177,10 +177,10 @@ InvoiceEntity? _removeQuoteItem(InvoiceEntity? quote, DeleteQuoteItem action) {
 }
 
 InvoiceEntity? _updateQuoteItem(InvoiceEntity? quote, UpdateQuoteItem action) {
-  if (quote!.lineItems.length <= action.index!) {
+  if (quote!.lineItems.length <= action.index) {
     return quote;
   }
-  return quote.rebuild((b) => b..lineItems[action.index!] = action.quoteItem);
+  return quote.rebuild((b) => b..lineItems[action.index] = action.quoteItem);
 }
 
 final quoteListReducer = combineReducers<ListUIState>([
diff --git a/lib/redux/recurring_invoice/recurring_invoice_actions.dart b/lib/redux/recurring_invoice/recurring_invoice_actions.dart
index 9b166758d..1f388b8c8 100644
--- a/lib/redux/recurring_invoice/recurring_invoice_actions.dart
+++ b/lib/redux/recurring_invoice/recurring_invoice_actions.dart
@@ -223,10 +223,13 @@ class AddRecurringInvoiceItems implements PersistUI {
 }
 
 class UpdateRecurringInvoiceItem implements PersistUI {
-  UpdateRecurringInvoiceItem({this.index, this.item});
+  UpdateRecurringInvoiceItem({
+    required this.index,
+    required this.item,
+  });
 
-  final int? index;
-  final InvoiceItemEntity? item;
+  final int index;
+  final InvoiceItemEntity item;
 }
 
 class DeleteRecurringInvoiceItem implements PersistUI {
diff --git a/lib/redux/recurring_invoice/recurring_invoice_middleware.dart b/lib/redux/recurring_invoice/recurring_invoice_middleware.dart
index c47027da6..da1e44a92 100644
--- a/lib/redux/recurring_invoice/recurring_invoice_middleware.dart
+++ b/lib/redux/recurring_invoice/recurring_invoice_middleware.dart
@@ -335,7 +335,7 @@ Middleware<AppState> _saveRecurringInvoice(
     // remove any empty line items
     final updatedInvoice = action.recurringInvoice!.rebuild((b) => b
       ..lineItems.replace(
-          action.recurringInvoice!.lineItems.where((item) => !item!.isEmpty)));
+          action.recurringInvoice!.lineItems.where((item) => !item.isEmpty)));
 
     repository
         .saveData(store.state.credentials, updatedInvoice,
diff --git a/lib/redux/recurring_invoice/recurring_invoice_reducer.dart b/lib/redux/recurring_invoice/recurring_invoice_reducer.dart
index 19fe10ac8..2c906c6bd 100644
--- a/lib/redux/recurring_invoice/recurring_invoice_reducer.dart
+++ b/lib/redux/recurring_invoice/recurring_invoice_reducer.dart
@@ -217,11 +217,11 @@ InvoiceEntity? _removeRecurringInvoiceItem(
 
 InvoiceEntity? _updateRecurringInvoiceItem(
     InvoiceEntity? recurringInvoice, UpdateRecurringInvoiceItem action) {
-  if (recurringInvoice!.lineItems.length <= action.index!) {
+  if (recurringInvoice!.lineItems.length <= action.index) {
     return recurringInvoice;
   }
   return recurringInvoice
-      .rebuild((b) => b..lineItems[action.index!] = action.item);
+      .rebuild((b) => b..lineItems[action.index] = action.item);
 }
 
 final recurringInvoiceListReducer = combineReducers<ListUIState>([
diff --git a/lib/ui/credit/edit/credit_edit.dart b/lib/ui/credit/edit/credit_edit.dart
index a1b82c43b..baa9367d8 100644
--- a/lib/ui/credit/edit/credit_edit.dart
+++ b/lib/ui/credit/edit/credit_edit.dart
@@ -158,8 +158,8 @@ class _CreditEditState extends State<CreditEdit>
                   invoice: invoice,
                   showTasksAndExpenses: false,
                   excluded: invoice.lineItems
-                      .where((item) => item!.isTask || item.isExpense)
-                      .map((item) => item!.isTask
+                      .where((item) => item.isTask || item.isExpense)
+                      .map((item) => item.isTask
                           ? viewModel.state!.taskState.map[item.taskId]
                           : viewModel.state!.expenseState.map[item.expenseId])
                       .toList(),
diff --git a/lib/ui/invoice/edit/invoice_edit.dart b/lib/ui/invoice/edit/invoice_edit.dart
index 660fd4b7a..c4e32be51 100644
--- a/lib/ui/invoice/edit/invoice_edit.dart
+++ b/lib/ui/invoice/edit/invoice_edit.dart
@@ -173,8 +173,8 @@ class _InvoiceEditState extends State<InvoiceEdit>
                   invoice: invoice,
                   showTasksAndExpenses: true,
                   excluded: invoice.lineItems
-                      .where((item) => item!.isTask || item.isExpense)
-                      .map((item) => item!.isTask
+                      .where((item) => item.isTask || item.isExpense)
+                      .map((item) => item.isTask
                           ? viewModel.state!.taskState.map[item.taskId]
                           : viewModel.state!.expenseState.map[item.expenseId])
                       .toList(),
diff --git a/lib/ui/invoice/edit/invoice_edit_desktop.dart b/lib/ui/invoice/edit/invoice_edit_desktop.dart
index a3191f0d1..03e30d542 100644
--- a/lib/ui/invoice/edit/invoice_edit_desktop.dart
+++ b/lib/ui/invoice/edit/invoice_edit_desktop.dart
@@ -243,11 +243,11 @@ class InvoiceEditDesktopState extends State<InvoiceEditDesktop>
 
     final countProducts = invoice.lineItems
         .where((item) =>
-            !item!.isEmpty && item.typeId != InvoiceItemEntity.TYPE_TASK)
+            !item.isEmpty && item.typeId != InvoiceItemEntity.TYPE_TASK)
         .length;
     final countTasks = invoice.lineItems
         .where((item) =>
-            !item!.isEmpty && item.typeId == InvoiceItemEntity.TYPE_TASK)
+            !item.isEmpty && item.typeId == InvoiceItemEntity.TYPE_TASK)
         .length;
 
     final showTasksTable = (invoice.hasTasks || company.showTasksTable) &&
diff --git a/lib/ui/invoice/edit/invoice_edit_items.dart b/lib/ui/invoice/edit/invoice_edit_items.dart
index 99e89bf67..c7806ea20 100644
--- a/lib/ui/invoice/edit/invoice_edit_items.dart
+++ b/lib/ui/invoice/edit/invoice_edit_items.dart
@@ -46,7 +46,7 @@ class _InvoiceEditItemsState extends State<InvoiceEditItems> {
             viewModel: viewModel,
             entityViewModel: widget.entityViewModel,
             key: ValueKey('__${lineItemIndex}__'),
-            invoiceItem: invoice.lineItems[lineItemIndex!]!,
+            invoiceItem: invoice.lineItems[lineItemIndex!],
             index: lineItemIndex,
           );
         });
diff --git a/lib/ui/invoice/edit/invoice_edit_items_desktop.dart b/lib/ui/invoice/edit/invoice_edit_items_desktop.dart
index 8242b37e6..a89ea3431 100644
--- a/lib/ui/invoice/edit/invoice_edit_items_desktop.dart
+++ b/lib/ui/invoice/edit/invoice_edit_items_desktop.dart
@@ -82,18 +82,18 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
     final company = state.company;
 
     final includedLineItems = lineItems.where((lineItem) {
-      return (lineItem!.typeId == InvoiceItemEntity.TYPE_TASK &&
+      return (lineItem.typeId == InvoiceItemEntity.TYPE_TASK &&
               widget.isTasks) ||
           (lineItem.typeId != InvoiceItemEntity.TYPE_TASK && !widget.isTasks) ||
           lineItem.isEmpty;
     }).toList();
 
     final hasTax1 = company.enableFirstItemTaxRate ||
-        includedLineItems.any((item) => item!.taxName1.isNotEmpty);
+        includedLineItems.any((item) => item.taxName1.isNotEmpty);
     final hasTax2 = company.enableSecondItemTaxRate ||
-        includedLineItems.any((item) => item!.taxName2.isNotEmpty);
+        includedLineItems.any((item) => item.taxName2.isNotEmpty);
     final hasTax3 = company.enableThirdItemTaxRate ||
-        includedLineItems.any((item) => item!.taxName3.isNotEmpty);
+        includedLineItems.any((item) => item.taxName3.isNotEmpty);
     final hasAnyTax = hasTax1 || hasTax2 || hasTax3;
 
     final customField1 =
@@ -292,7 +292,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
         state.staticState.currencyMap[client.currencyId]?.precision ?? 2;
     final lineItems = invoice.lineItems.toList();
     final includedLineItems = lineItems.where((lineItem) {
-      return (lineItem!.typeId == InvoiceItemEntity.TYPE_TASK &&
+      return (lineItem.typeId == InvoiceItemEntity.TYPE_TASK &&
               widget.isTasks) ||
           (lineItem.typeId != InvoiceItemEntity.TYPE_TASK && !widget.isTasks) ||
           lineItem.isEmpty;
@@ -429,7 +429,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
             buildDefaultDragHandles: false,
             itemCount: lineItems.length,
             itemBuilder: (context, index) {
-              final item = lineItems[index]!;
+              final item = lineItems[index];
 
               if ((item.typeId == InvoiceItemEntity.TYPE_TASK &&
                       !widget.isTasks) ||
@@ -577,7 +577,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
       );
     }
 
-    if (lineItems.where((item) => item!.isEmpty).isEmpty) {
+    if (lineItems.where((item) => item.isEmpty).isEmpty) {
       lineItems.add(InvoiceItemEntity(
           quantity: company.defaultQuantity || !company.enableProductQuantity
               ? 1
@@ -594,7 +594,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
         color: tableFontColor.isNotEmpty
             ? convertHexStringToColor(tableFontColor)
             : null,
-        onPressed: includedLineItems.where((item) => !item!.isEmpty).length < 2
+        onPressed: includedLineItems.where((item) => !item.isEmpty).length < 2
             ? null
             : () {
                 setState(() => _isReordering = !_isReordering);
@@ -623,14 +623,14 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                 : BoxDecoration(),
           ),
           for (var index = 0; index < lineItems.length; index++)
-            if ((lineItems[index]!.typeId == InvoiceItemEntity.TYPE_TASK &&
+            if ((lineItems[index].typeId == InvoiceItemEntity.TYPE_TASK &&
                     widget.isTasks) ||
-                (lineItems[index]!.typeId != InvoiceItemEntity.TYPE_TASK &&
+                (lineItems[index].typeId != InvoiceItemEntity.TYPE_TASK &&
                     !widget.isTasks) ||
-                lineItems[index]!.isEmpty)
+                lineItems[index].isEmpty)
               TableRow(
                   key: ValueKey(
-                      '__line_item_${index}_${lineItems[index]!.createdAt}__'),
+                      '__line_item_${index}_${lineItems[index].createdAt}__'),
                   children: [
                     ..._columns.map((column) {
                       if (column == COLUMN_ITEM) {
@@ -647,7 +647,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                               key: ValueKey('__line_item_${index}_name__'),
                               textEditingController: _textEditingController,
                               initialValue: TextEditingValue(
-                                  text: lineItems[index]!.productKey),
+                                  text: lineItems[index].productKey),
                               optionsBuilder:
                                   (TextEditingValue textEditingValue) {
                                 final options = productIds
@@ -672,8 +672,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
 
                                 if (options.length == 1 &&
                                     options[0].productKey.toLowerCase() ==
-                                        lineItems[index]!
-                                            .productKey
+                                        lineItems[index].productKey
                                             .toLowerCase()) {
                                   return <ProductEntity>[];
                                 }
@@ -706,7 +705,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                 }
 
                                 final updatedItem = company.fillProducts
-                                    ? item!.rebuild((b) => b
+                                    ? item.rebuild((b) => b
                                       ..productKey = product.productKey
                                       ..notes = item.isTask
                                           ? item.notes
@@ -756,7 +755,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                                   product.taxName3.isNotEmpty
                                               ? product.taxRate3
                                               : item.taxRate3)
-                                    : item!.rebuild((b) =>
+                                    : item.rebuild((b) =>
                                         b..productKey = product.productKey);
 
                                 _onChanged(updatedItem, index, debounce: false);
@@ -777,7 +776,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                   },
                                   onChanged: (value) {
                                     _onChanged(
-                                        lineItems[index]!.rebuild(
+                                        lineItems[index].rebuild(
                                             (b) => b..productKey = value),
                                         index);
                                   },
@@ -865,10 +864,9 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                               key: ValueKey(
                                   '__line_item_${index}_description__'),
                               autofocus: _autocompleteFocusIndex == index,
-                              initialValue: lineItems[index]!.notes,
+                              initialValue: lineItems[index].notes,
                               onChanged: (value) => _onChanged(
-                                  lineItems[index]!
-                                      .rebuild((b) => b..notes = value),
+                                  lineItems[index].rebuild((b) => b..notes = value),
                                   index),
                             ),
                           ),
@@ -882,11 +880,10 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                 const EdgeInsets.only(right: kTableColumnGap),
                             child: CustomField(
                               field: customField1,
-                              value: lineItems[index]!.customValue1,
+                              value: lineItems[index].customValue1,
                               hideFieldLabel: true,
                               onChanged: (value) => _onChanged(
-                                  lineItems[index]!
-                                      .rebuild((b) => b..customValue1 = value),
+                                  lineItems[index].rebuild((b) => b..customValue1 = value),
                                   index),
                               onSavePressed:
                                   widget.entityViewModel.onSavePressed,
@@ -902,11 +899,10 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                 const EdgeInsets.only(right: kTableColumnGap),
                             child: CustomField(
                               field: customField2,
-                              value: lineItems[index]!.customValue2,
+                              value: lineItems[index].customValue2,
                               hideFieldLabel: true,
                               onChanged: (value) => _onChanged(
-                                  lineItems[index]!
-                                      .rebuild((b) => b..customValue2 = value),
+                                  lineItems[index].rebuild((b) => b..customValue2 = value),
                                   index),
                               onSavePressed:
                                   widget.entityViewModel.onSavePressed,
@@ -922,11 +918,10 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                 const EdgeInsets.only(right: kTableColumnGap),
                             child: CustomField(
                               field: customField3,
-                              value: lineItems[index]!.customValue3,
+                              value: lineItems[index].customValue3,
                               hideFieldLabel: true,
                               onChanged: (value) => _onChanged(
-                                  lineItems[index]!
-                                      .rebuild((b) => b..customValue3 = value),
+                                  lineItems[index].rebuild((b) => b..customValue3 = value),
                                   index),
                               onSavePressed:
                                   widget.entityViewModel.onSavePressed,
@@ -942,11 +937,10 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                 const EdgeInsets.only(right: kTableColumnGap),
                             child: CustomField(
                               field: customField4,
-                              value: lineItems[index]!.customValue4,
+                              value: lineItems[index].customValue4,
                               hideFieldLabel: true,
                               onChanged: (value) => _onChanged(
-                                  lineItems[index]!
-                                      .rebuild((b) => b..customValue4 = value),
+                                  lineItems[index].rebuild((b) => b..customValue4 = value),
                                   index),
                               onSavePressed:
                                   widget.entityViewModel.onSavePressed,
@@ -954,7 +948,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                           ),
                         );
                       } else if (column == COLUMN_TAX_CATEGORY &&
-                          !lineItems[index]!.hasOverrideTax) {
+                          !lineItems[index].hasOverrideTax) {
                         return Focus(
                           onFocusChange: (hasFocus) => _onFocusChange(),
                           skipTraversal: true,
@@ -963,9 +957,9 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                 const EdgeInsets.only(right: kTableColumnGap),
                             child: AppDropdownButton<String>(
                                 labelText: '',
-                                value: lineItems[index]!.taxCategoryId,
+                                value: lineItems[index].taxCategoryId,
                                 onChanged: (dynamic value) => _onChanged(
-                                    lineItems[index]!.rebuild(
+                                    lineItems[index].rebuild(
                                         (b) => b..taxCategoryId = value),
                                     index),
                                 items: kTaxCategories.keys
@@ -980,7 +974,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                         );
                       } else if (column == COLUMN_TAX1 ||
                           (column == COLUMN_TAX_CATEGORY &&
-                              lineItems[index]!.hasOverrideTax)) {
+                              lineItems[index].hasOverrideTax)) {
                         Widget child = Focus(
                           onFocusChange: (hasFocus) => _onFocusChange(),
                           skipTraversal: true,
@@ -989,27 +983,27 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                 const EdgeInsets.only(right: kTableColumnGap),
                             child: TaxRateDropdown(
                               onSelected: (taxRate) => _onChanged(
-                                lineItems[index]!.rebuild((b) => b
+                                lineItems[index].rebuild((b) => b
                                   ..taxName1 = taxRate.name
                                   ..taxRate1 = taxRate.rate),
                                 index,
                                 debounce: false,
                               ),
                               labelText: null,
-                              initialTaxName: lineItems[index]!.taxName1,
-                              initialTaxRate: lineItems[index]!.taxRate1,
+                              initialTaxName: lineItems[index].taxName1,
+                              initialTaxRate: lineItems[index].taxRate1,
                             ),
                           ),
                         );
 
-                        if (lineItems[index]!.hasOverrideTax) {
+                        if (lineItems[index].hasOverrideTax) {
                           child = Row(
                             children: [
                               Expanded(child: child),
                               IconButton(
                                   visualDensity: VisualDensity.compact,
                                   onPressed: () => _onChanged(
-                                      lineItems[index]!.rebuild((b) => b
+                                      lineItems[index].rebuild((b) => b
                                         ..taxName1 = ''
                                         ..taxRate1 = 0
                                         ..taxCategoryId = kTaxCategoryPhysical),
@@ -1029,15 +1023,15 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                 const EdgeInsets.only(right: kTableColumnGap),
                             child: TaxRateDropdown(
                               onSelected: (taxRate) => _onChanged(
-                                lineItems[index]!.rebuild((b) => b
+                                lineItems[index].rebuild((b) => b
                                   ..taxName2 = taxRate.name
                                   ..taxRate2 = taxRate.rate),
                                 index,
                                 debounce: false,
                               ),
                               labelText: null,
-                              initialTaxName: lineItems[index]!.taxName2,
-                              initialTaxRate: lineItems[index]!.taxRate2,
+                              initialTaxName: lineItems[index].taxName2,
+                              initialTaxRate: lineItems[index].taxRate2,
                             ),
                           ),
                         );
@@ -1050,15 +1044,15 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                 const EdgeInsets.only(right: kTableColumnGap),
                             child: TaxRateDropdown(
                               onSelected: (taxRate) => _onChanged(
-                                lineItems[index]!.rebuild((b) => b
+                                lineItems[index].rebuild((b) => b
                                   ..taxName3 = taxRate.name
                                   ..taxRate3 = taxRate.rate),
                                 index,
                                 debounce: false,
                               ),
                               labelText: null,
-                              initialTaxName: lineItems[index]!.taxName3,
-                              initialTaxRate: lineItems[index]!.taxRate3,
+                              initialTaxName: lineItems[index].taxName3,
+                              initialTaxRate: lineItems[index].taxRate3,
                             ),
                           ),
                         );
@@ -1073,7 +1067,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                               key: ValueKey('__line_item_${index}_cost__'),
                               textAlign: TextAlign.right,
                               initialValue: formatNumber(
-                                lineItems[index]!.cost,
+                                lineItems[index].cost,
                                 context,
                                 formatNumberType: FormatNumberType.inputMoney,
                                 clientId: invoice.isPurchaseOrder
@@ -1084,7 +1078,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                     : null,
                               ),
                               onChanged: (value) => _onChanged(
-                                lineItems[index]!.rebuild(
+                                lineItems[index].rebuild(
                                     (b) => b..cost = parseDouble(value)),
                                 index,
                                 debounce: false,
@@ -1107,7 +1101,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                               key: ValueKey('__line_item_${index}_quantity__'),
                               textAlign: TextAlign.right,
                               initialValue: formatNumber(
-                                lineItems[index]!.quantity,
+                                lineItems[index].quantity,
                                 context,
                                 formatNumberType: FormatNumberType.inputAmount,
                                 clientId: invoice.isPurchaseOrder
@@ -1118,7 +1112,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                     : null,
                               ),
                               onChanged: (value) => _onChanged(
-                                lineItems[index]!.rebuild(
+                                lineItems[index].rebuild(
                                     (b) => b..quantity = parseDouble(value)),
                                 index,
                                 debounce: false,
@@ -1141,7 +1135,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                               key: ValueKey('__line_item_${index}_discount__'),
                               textAlign: TextAlign.right,
                               initialValue: formatNumber(
-                                lineItems[index]!.discount,
+                                lineItems[index].discount,
                                 context,
                                 formatNumberType: FormatNumberType.inputAmount,
                                 clientId: invoice.isPurchaseOrder
@@ -1152,7 +1146,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                                     : null,
                               ),
                               onChanged: (value) => _onChanged(
-                                  lineItems[index]!.rebuild(
+                                  lineItems[index].rebuild(
                                       (b) => b..discount = parseDouble(value)),
                                   index),
                               keyboardType: TextInputType.numberWithOptions(
@@ -1170,11 +1164,11 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                       padding: const EdgeInsets.only(right: kTableColumnGap),
                       child: TextFormField(
                         key: ValueKey(
-                            '__total_${index}_${lineItems[index]!.total(invoice, precision)}_${invoice.clientId}__'),
+                            '__total_${index}_${lineItems[index].total(invoice, precision)}_${invoice.clientId}__'),
                         readOnly: true,
                         enabled: false,
                         initialValue: formatNumber(
-                          lineItems[index]!.total(invoice, precision),
+                          lineItems[index].total(invoice, precision),
                           context,
                           clientId:
                               invoice.isPurchaseOrder ? null : invoice.clientId,
@@ -1186,13 +1180,13 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                     ),
                     PopupMenuButton<String>(
                       icon: Icon(Icons.more_vert),
-                      enabled: !lineItems[index]!.isEmpty,
+                      enabled: !lineItems[index].isEmpty,
                       itemBuilder: (BuildContext context) {
                         final sectionIndex =
                             includedLineItems.indexOf(lineItems[index]);
                         final options = {
                           if (widget.isTasks &&
-                              (lineItems[index]!.taskId ?? '').isNotEmpty)
+                              (lineItems[index].taskId ?? '').isNotEmpty)
                             localization.viewTask: MdiIcons.chevronDoubleRight,
                           if (sectionIndex > 0)
                             localization.moveTop: MdiIcons.chevronDoubleUp,
@@ -1218,7 +1212,7 @@ class _InvoiceEditItemsDesktopState extends State<InvoiceEditItemsDesktop> {
                       onSelected: (String action) {
                         if (action == localization.viewTask) {
                           viewEntityById(
-                              entityId: lineItems[index]!.taskId,
+                              entityId: lineItems[index].taskId,
                               entityType: EntityType.task);
                         } else if (action == localization.moveTop) {
                           viewModel.onMovedInvoiceItem!(index, 0);
diff --git a/lib/ui/invoice/edit/invoice_edit_vm.dart b/lib/ui/invoice/edit/invoice_edit_vm.dart
index 3bd877048..90491f1d1 100644
--- a/lib/ui/invoice/edit/invoice_edit_vm.dart
+++ b/lib/ui/invoice/edit/invoice_edit_vm.dart
@@ -124,7 +124,7 @@ class InvoiceEditVM extends AbstractInvoiceEditVM {
           final state = store.state;
           final clientId = invoice.clientId;
           for (int i = 0; i < invoice.lineItems.length; i++) {
-            final lineItem = invoice.lineItems[i]!;
+            final lineItem = invoice.lineItems[i];
             final task = state.taskState.get(lineItem.taskId ?? '');
             if (task.clientId.isNotEmpty && task.clientId != clientId) {
               showDialog<ErrorDialog>(
diff --git a/lib/ui/purchase_order/edit/purchase_order_edit.dart b/lib/ui/purchase_order/edit/purchase_order_edit.dart
index 3d097fa1a..f37668ad3 100644
--- a/lib/ui/purchase_order/edit/purchase_order_edit.dart
+++ b/lib/ui/purchase_order/edit/purchase_order_edit.dart
@@ -161,8 +161,8 @@ class _PurchaseOrderEditState extends State<PurchaseOrderEdit>
                   invoice: invoice,
                   showTasksAndExpenses: false,
                   excluded: invoice.lineItems
-                      .where((item) => item!.isTask || item.isExpense)
-                      .map((item) => item!.isTask
+                      .where((item) => item.isTask || item.isExpense)
+                      .map((item) => item.isTask
                           ? viewModel.state!.taskState.map[item.taskId]
                           : viewModel.state!.expenseState.map[item.expenseId])
                       .toList(),
diff --git a/lib/ui/quote/edit/quote_edit.dart b/lib/ui/quote/edit/quote_edit.dart
index c4dd33387..8370c2fc4 100644
--- a/lib/ui/quote/edit/quote_edit.dart
+++ b/lib/ui/quote/edit/quote_edit.dart
@@ -158,8 +158,8 @@ class _QuoteEditState extends State<QuoteEdit>
                   invoice: invoice,
                   showTasksAndExpenses: false,
                   excluded: invoice.lineItems
-                      .where((item) => item!.isTask || item.isExpense)
-                      .map((item) => item!.isTask
+                      .where((item) => item.isTask || item.isExpense)
+                      .map((item) => item.isTask
                           ? viewModel.state!.taskState.map[item.taskId]
                           : viewModel.state!.expenseState.map[item.expenseId])
                       .toList(),
diff --git a/lib/ui/recurring_invoice/edit/recurring_invoice_edit.dart b/lib/ui/recurring_invoice/edit/recurring_invoice_edit.dart
index f6bea62e1..6ee326aed 100644
--- a/lib/ui/recurring_invoice/edit/recurring_invoice_edit.dart
+++ b/lib/ui/recurring_invoice/edit/recurring_invoice_edit.dart
@@ -161,8 +161,8 @@ class _RecurringInvoiceEditState extends State<RecurringInvoiceEdit>
                   invoice: invoice,
                   showTasksAndExpenses: false,
                   excluded: invoice.lineItems
-                      .where((item) => item!.isTask || item.isExpense)
-                      .map((item) => item!.isTask
+                      .where((item) => item.isTask || item.isExpense)
+                      .map((item) => item.isTask
                           ? viewModel.state!.taskState.map[item.taskId]
                           : viewModel.state!.expenseState.map[item.expenseId])
                       .toList(),
diff --git a/lib/ui/reports/credit_item_report.dart b/lib/ui/reports/credit_item_report.dart
index f4346156c..bd3817899 100644
--- a/lib/ui/reports/credit_item_report.dart
+++ b/lib/ui/reports/credit_item_report.dart
@@ -113,7 +113,7 @@ ReportResult lineItemReport(
 
       for (var column in columns) {
         dynamic value = '';
-        final productId = productKeyMap[lineItem!.productKey];
+        final productId = productKeyMap[lineItem.productKey];
 
         switch (column) {
           case CreditItemReportFields.price:
diff --git a/lib/ui/reports/invoice_item_report.dart b/lib/ui/reports/invoice_item_report.dart
index dae2e35cd..f115520a1 100644
--- a/lib/ui/reports/invoice_item_report.dart
+++ b/lib/ui/reports/invoice_item_report.dart
@@ -113,7 +113,7 @@ ReportResult lineItemReport(
 
       for (var column in columns) {
         dynamic value = '';
-        final productId = productKeyMap[lineItem!.productKey];
+        final productId = productKeyMap[lineItem.productKey];
 
         switch (column) {
           case InvoiceItemReportFields.price:
diff --git a/lib/ui/reports/purchase_order_item_report.dart b/lib/ui/reports/purchase_order_item_report.dart
index 0e462af5b..213f10a26 100644
--- a/lib/ui/reports/purchase_order_item_report.dart
+++ b/lib/ui/reports/purchase_order_item_report.dart
@@ -115,7 +115,7 @@ ReportResult lineItemReport(
 
       for (var column in columns) {
         dynamic value = '';
-        final productId = productKeyMap[lineItem!.productKey];
+        final productId = productKeyMap[lineItem.productKey];
 
         switch (column) {
           case PurchaseOrderItemReportFields.price:
diff --git a/lib/ui/reports/quote_item_report.dart b/lib/ui/reports/quote_item_report.dart
index db02f964c..66061fa4c 100644
--- a/lib/ui/reports/quote_item_report.dart
+++ b/lib/ui/reports/quote_item_report.dart
@@ -113,7 +113,7 @@ ReportResult lineItemReport(
 
       for (var column in columns) {
         dynamic value = '';
-        final productId = productKeyMap[lineItem!.productKey];
+        final productId = productKeyMap[lineItem.productKey];
 
         switch (column) {
           case QuoteItemReportFields.price: