diff --git a/Sources/ChatFeature/Controllers/GroupChatController.swift b/Sources/ChatFeature/Controllers/GroupChatController.swift
index cbcabb54ac827e27e98614ad1ae5a2d81c5dc613..b168e70c438b6660f637758270bc28761dfa5c0c 100644
--- a/Sources/ChatFeature/Controllers/GroupChatController.swift
+++ b/Sources/ChatFeature/Controllers/GroupChatController.swift
@@ -375,7 +375,7 @@ extension GroupChatController: UICollectionViewDataSource {
                 Bubbler.buildReplyGroup(
                     bubble: cell.rightView,
                     with: item,
-                    reply: replyContent(item.replyMessageId),
+                    reply: replyContent(replyMessageId),
                     sender: name(item.senderId)
                 )
 
@@ -404,7 +404,7 @@ extension GroupChatController: UICollectionViewDataSource {
                 Bubbler.buildReplyGroup(
                     bubble: cell.rightView,
                     with: item,
-                    reply: replyContent(item.replyMessageId),
+                    reply: replyContent(replyMessageId),
                     sender: name(item.senderId)
                 )
 
diff --git a/Sources/ContactFeature/Controllers/ContactController.swift b/Sources/ContactFeature/Controllers/ContactController.swift
index 5dd2b37eb68790365da473f6a5c9e9acbb535a34..1ef8e96ffba5f58ec2ae2ac6e03adc701e1b3ffb 100644
--- a/Sources/ContactFeature/Controllers/ContactController.swift
+++ b/Sources/ContactFeature/Controllers/ContactController.swift
@@ -169,7 +169,7 @@ public final class ContactController: UIViewController {
             .sink { [unowned self] in
                 coordinator.toNickname(
                     from: self,
-                    prefilled: viewModel.contact.nickname ?? viewModel.contact.username!,
+                    prefilled: (viewModel.contact.nickname ?? viewModel.contact.username) ?? "",
                     viewModel.didTapRequest(with:)
                 )
             }.store(in: &cancellables)
@@ -181,7 +181,7 @@ public final class ContactController: UIViewController {
             .sink { [unowned self] in
                 coordinator.toNickname(
                     from: self,
-                    prefilled: viewModel.contact.nickname ?? viewModel.contact.username!,
+                    prefilled: (viewModel.contact.nickname ?? viewModel.contact.username) ?? "",
                     viewModel.didTapAccept(_:)
                 )
             }.store(in: &cancellables)
@@ -243,7 +243,7 @@ public final class ContactController: UIViewController {
                     .sink { [unowned self] in
                         coordinator.toNickname(
                             from: self,
-                            prefilled: viewModel.contact.nickname ?? viewModel.contact.username!,
+                            prefilled: (viewModel.contact.nickname ?? viewModel.contact.username) ?? "",
                             viewModel.didUpdateNickname(_:)
                         )
                     }
diff --git a/Sources/ContactListFeature/Controllers/CreateGroupController.swift b/Sources/ContactListFeature/Controllers/CreateGroupController.swift
index 73c9f8b18595cc242a07e66c7d253c51cf573921..9e9d039dd5e5fe2dd4adfa179fc736ab51fa6c4b 100644
--- a/Sources/ContactListFeature/Controllers/CreateGroupController.swift
+++ b/Sources/ContactListFeature/Controllers/CreateGroupController.swift
@@ -74,7 +74,8 @@ public final class CreateGroupController: UIViewController {
         ) { [weak viewModel] collectionView, indexPath, contact in
             let cell: CreateGroupCollectionCell = collectionView.dequeueReusableCell(forIndexPath: indexPath)
 
-            cell.setup(title: contact.nickname ?? contact.username!, image: contact.photo)
+            let title = (contact.nickname ?? contact.username) ?? ""
+            cell.setup(title: title, image: contact.photo)
             cell.didTapRemove = { viewModel?.didSelect(contact: contact) }
 
             return cell
@@ -84,8 +85,9 @@ public final class CreateGroupController: UIViewController {
             tableView: screenView.tableView
         ) { [weak self] tableView, indexPath, contact in
             let cell = tableView.dequeueReusableCell(forIndexPath: indexPath, ofType: SmallAvatarAndTitleCell.self)
-            cell.titleLabel.text = contact.nickname ?? contact.username
-            cell.avatarView.setupProfile(title: contact.nickname ?? contact.username!, image: contact.photo, size: .medium)
+            let title = (contact.nickname ?? contact.username) ?? ""
+            cell.titleLabel.text = title
+            cell.avatarView.setupProfile(title: title, image: contact.photo, size: .medium)
 
             if let selectedElements = self?.selectedElements, selectedElements.contains(contact) {
                 tableView.selectRow(at: indexPath, animated: true, scrollPosition: .none)
diff --git a/Sources/ContactListFeature/ViewModels/CreateGroupViewModel.swift b/Sources/ContactListFeature/ViewModels/CreateGroupViewModel.swift
index 38717ac21153c846c1165fa023369fc7b15305f1..70485e37b03b91b5d98d6f59f53c9f2a4dafa901 100644
--- a/Sources/ContactListFeature/ViewModels/CreateGroupViewModel.swift
+++ b/Sources/ContactListFeature/ViewModels/CreateGroupViewModel.swift
@@ -67,7 +67,11 @@ final class CreateGroupViewModel {
             return
         }
 
-        contactsRelay.send(allContacts.filter { $0.username!.contains(text.lowercased()) })
+        contactsRelay.send(
+            allContacts.filter {
+                ($0.username ?? "").contains(text.lowercased())
+            }
+        )
     }
 
     func create(name: String, welcome: String?, members: [Contact]) {
diff --git a/Sources/PushFeature/PushHandler.swift b/Sources/PushFeature/PushHandler.swift
index 4259476ed9000cbc5bd0440f443c26c59b81aa62..adb0feb4d96a9908ad9cc1990dd0d4f4c6af76e4 100644
--- a/Sources/PushFeature/PushHandler.swift
+++ b/Sources/PushFeature/PushHandler.swift
@@ -110,7 +110,7 @@ public final class PushHandler: PushHandling {
                 return ($0.type.unknownSenderContent!, $0)
             }
 
-            let name = contact.nickname ?? contact.username!
+            let name = (contact.nickname ?? contact.username) ?? ""
             return ($0.type.knownSenderContent(name)!, $0)
         }
 
diff --git a/Sources/RequestsFeature/Controllers/RequestsReceivedController.swift b/Sources/RequestsFeature/Controllers/RequestsReceivedController.swift
index e9de6a320d86525050224105aa8e6fa1d374b733..5edb77726fa6d43ba7d4e2a816192fcadd39303b 100644
--- a/Sources/RequestsFeature/Controllers/RequestsReceivedController.swift
+++ b/Sources/RequestsFeature/Controllers/RequestsReceivedController.swift
@@ -212,7 +212,7 @@ extension RequestsReceivedController {
 
         let drawerNickname = DrawerText(
             font: Fonts.Mulish.extraBold.font(size: 26.0),
-            text: contact.nickname ?? contact.username!,
+            text: (contact.nickname ?? contact.username) ?? "",
             color: Asset.neutralDark.color,
             spacingAfter: 20
         )
@@ -393,7 +393,7 @@ extension RequestsReceivedController {
 
         let drawerUsername = DrawerText(
             font: Fonts.Mulish.extraBold.font(size: 26.0),
-            text: contact.username!,
+            text: contact.username ?? "",
             color: Asset.neutralDark.color,
             spacingAfter: 25
         )
@@ -453,7 +453,7 @@ extension RequestsReceivedController {
         items.append(drawerNicknameTitle)
 
         let drawerNicknameInput = DrawerInput(
-            placeholder: contact.username!,
+            placeholder: contact.username ?? "",
             validator: .init(
                 wrongIcon: .image(Asset.sharedError.image),
                 correctIcon: .image(Asset.sharedSuccess.image),
diff --git a/Sources/RequestsFeature/Views/RequestCell.swift b/Sources/RequestsFeature/Views/RequestCell.swift
index d82093630e165f487d023eca2b099f5447492a37..e0af9ec6017ef1241ed0831ee0dbad71af7dc3d4 100644
--- a/Sources/RequestsFeature/Views/RequestCell.swift
+++ b/Sources/RequestsFeature/Views/RequestCell.swift
@@ -89,7 +89,7 @@ final class RequestCell: UICollectionViewCell {
         }
 
         setupContact(
-            title: contact.nickname ?? contact.username!,
+            title: (contact.nickname ?? contact.username) ?? "",
             photo: contact.photo,
             phone: phone,
             email: contact.email,
@@ -128,7 +128,7 @@ final class RequestCell: UICollectionViewCell {
         }
 
         setupContact(
-            title: contact.nickname ?? contact.username!,
+            title: (contact.nickname ?? contact.username) ?? "",
             photo: contact.photo,
             phone: phone,
             email: contact.email,
@@ -165,7 +165,7 @@ final class RequestCell: UICollectionViewCell {
             }
 
             setupContact(
-                title: contact.nickname ?? contact.username!,
+                title: (contact.nickname ?? contact.username) ?? "",
                 photo: contact.photo,
                 phone: phone,
                 email: contact.email,