diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1493974..b47cd98 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,27 @@ called out explicitly even when nothing else did.
 release notes, so a version with no entry here does not release. Write the entry in the same PR that
 syncs the contract, while the diff is still in front of you.
 
+## 0.4.0
+
+Synced to [`flipcash2-protobuf-api@0b56e3cd`](https://github.com/code-payments/flipcash2-protobuf-api/commit/0b56e3cd9a9f380f86a09664f09695a2254d7b0a).
+
+### Added
+
+- `message_edit_window` and `message_delete_window` on `account.v1.UserFlags`, both
+  `google.protobuf.Duration`, on fields 17 and 18. Each is the window after a message is created
+  during which that message can still be edited or deleted.
+
+  They are message-typed, so they carry explicit presence and an unset value is not a zero duration.
+  Check `hasMessageEditWindow` / `hasMessageDeleteWindow` in Swift, or `hasMessageEditWindow()` in
+  Kotlin, before reading either one. A server that has not set them leaves them absent, and reading
+  the field directly would report a zero-length window rather than no configured window.
+
+### Unchanged
+
+Nothing existing changed. No services, RPCs, messages, or fields were removed or reshaped, no result
+enum gained or reordered a case, and nothing was renumbered: `username_min_balance` keeps field 16,
+and every field before it keeps its number. The upgrade from `0.3.0` is free for both languages.
+
 ## 0.3.0
 
 No contract change. `flipcash2.lock` points at the same upstream commit as `0.2.0`, and the generated
diff --git a/Sources/Flipcash2ClientProtocol/account_v1_flipcash_account_service.pb.swift b/Sources/Flipcash2ClientProtocol/account_v1_flipcash_account_service.pb.swift
index 10519db..0ad6675 100644
--- a/Sources/Flipcash2ClientProtocol/account_v1_flipcash_account_service.pb.swift
+++ b/Sources/Flipcash2ClientProtocol/account_v1_flipcash_account_service.pb.swift
@@ -496,6 +496,26 @@ public struct Flipcash_Account_V1_UserFlags: @unchecked Sendable {
     set {_uniqueStorage()._usernameMinBalance = newValue}
   }
 
+  /// Duration after message creation when a message can be edited
+  public var messageEditWindow: SwiftProtobuf.Google_Protobuf_Duration {
+    get {return _storage._messageEditWindow ?? SwiftProtobuf.Google_Protobuf_Duration()}
+    set {_uniqueStorage()._messageEditWindow = newValue}
+  }
+  /// Returns true if `messageEditWindow` has been explicitly set.
+  public var hasMessageEditWindow: Bool {return _storage._messageEditWindow != nil}
+  /// Clears the value of `messageEditWindow`. Subsequent reads from it will return its default value.
+  public mutating func clearMessageEditWindow() {_uniqueStorage()._messageEditWindow = nil}
+
+  /// Duration after message creation when a message can be deleted
+  public var messageDeleteWindow: SwiftProtobuf.Google_Protobuf_Duration {
+    get {return _storage._messageDeleteWindow ?? SwiftProtobuf.Google_Protobuf_Duration()}
+    set {_uniqueStorage()._messageDeleteWindow = newValue}
+  }
+  /// Returns true if `messageDeleteWindow` has been explicitly set.
+  public var hasMessageDeleteWindow: Bool {return _storage._messageDeleteWindow != nil}
+  /// Clears the value of `messageDeleteWindow`. Subsequent reads from it will return its default value.
+  public mutating func clearMessageDeleteWindow() {_uniqueStorage()._messageDeleteWindow = nil}
+
   public var unknownFields = SwiftProtobuf.UnknownStorage()
 
   public enum OnRampProvider: SwiftProtobuf.Enum, Swift.CaseIterable {
@@ -976,7 +996,7 @@ extension Flipcash_Account_V1_GetUnauthenticatedUserFlagsResponse.Result: SwiftP
 
 extension Flipcash_Account_V1_UserFlags: SwiftProtobuf.Message, SwiftProtobuf._MessageImplementationBase, SwiftProtobuf._ProtoNameProviding {
   public static let protoMessageName: String = _protobuf_package + ".UserFlags"
-  public static let _protobuf_nameMap = SwiftProtobuf._NameMap(bytecode: "\0\u{3}is_registered_account\0\u{3}is_staff\0\u{3}requires_iap_for_registration\0\u{3}supported_on_ramp_providers\0\u{3}preferred_on_ramp_provider\0\u{3}min_build_number\0\u{3}bill_exchange_data_timeout\0\u{3}new_currency_purchase_amount\0\u{3}new_currency_fee_amount\0\u{3}withdrawal_fee_amount\0\u{3}preferred_on_ramp_usdc_liquidity_pool\0\u{3}enable_phone_number_send\0\u{3}minimum_holder_value\0\u{3}require_coinbase_email_verification\0\u{3}tip_presets\0\u{3}username_min_balance\0")
+  public static let _protobuf_nameMap = SwiftProtobuf._NameMap(bytecode: "\0\u{3}is_registered_account\0\u{3}is_staff\0\u{3}requires_iap_for_registration\0\u{3}supported_on_ramp_providers\0\u{3}preferred_on_ramp_provider\0\u{3}min_build_number\0\u{3}bill_exchange_data_timeout\0\u{3}new_currency_purchase_amount\0\u{3}new_currency_fee_amount\0\u{3}withdrawal_fee_amount\0\u{3}preferred_on_ramp_usdc_liquidity_pool\0\u{3}enable_phone_number_send\0\u{3}minimum_holder_value\0\u{3}require_coinbase_email_verification\0\u{3}tip_presets\0\u{3}username_min_balance\0\u{3}message_edit_window\0\u{3}message_delete_window\0")
 
   fileprivate class _StorageClass {
     var _isRegisteredAccount: Bool = false
@@ -995,6 +1015,8 @@ extension Flipcash_Account_V1_UserFlags: SwiftProtobuf.Message, SwiftProtobuf._M
     var _requireCoinbaseEmailVerification: Bool = false
     var _tipPresets: [Flipcash_Account_V1_TipPresets] = []
     var _usernameMinBalance: UInt64 = 0
+    var _messageEditWindow: SwiftProtobuf.Google_Protobuf_Duration? = nil
+    var _messageDeleteWindow: SwiftProtobuf.Google_Protobuf_Duration? = nil
 
       // This property is used as the initial default value for new instances of the type.
       // The type itself is protecting the reference to its storage via CoW semantics.
@@ -1021,6 +1043,8 @@ extension Flipcash_Account_V1_UserFlags: SwiftProtobuf.Message, SwiftProtobuf._M
       _requireCoinbaseEmailVerification = source._requireCoinbaseEmailVerification
       _tipPresets = source._tipPresets
       _usernameMinBalance = source._usernameMinBalance
+      _messageEditWindow = source._messageEditWindow
+      _messageDeleteWindow = source._messageDeleteWindow
     }
   }
 
@@ -1055,6 +1079,8 @@ extension Flipcash_Account_V1_UserFlags: SwiftProtobuf.Message, SwiftProtobuf._M
         case 14: try { try decoder.decodeSingularBoolField(value: &_storage._requireCoinbaseEmailVerification) }()
         case 15: try { try decoder.decodeRepeatedMessageField(value: &_storage._tipPresets) }()
         case 16: try { try decoder.decodeSingularUInt64Field(value: &_storage._usernameMinBalance) }()
+        case 17: try { try decoder.decodeSingularMessageField(value: &_storage._messageEditWindow) }()
+        case 18: try { try decoder.decodeSingularMessageField(value: &_storage._messageDeleteWindow) }()
         default: break
         }
       }
@@ -1115,6 +1141,12 @@ extension Flipcash_Account_V1_UserFlags: SwiftProtobuf.Message, SwiftProtobuf._M
       if _storage._usernameMinBalance != 0 {
         try visitor.visitSingularUInt64Field(value: _storage._usernameMinBalance, fieldNumber: 16)
       }
+      try { if let v = _storage._messageEditWindow {
+        try visitor.visitSingularMessageField(value: v, fieldNumber: 17)
+      } }()
+      try { if let v = _storage._messageDeleteWindow {
+        try visitor.visitSingularMessageField(value: v, fieldNumber: 18)
+      } }()
     }
     try unknownFields.traverse(visitor: &visitor)
   }
@@ -1140,6 +1172,8 @@ extension Flipcash_Account_V1_UserFlags: SwiftProtobuf.Message, SwiftProtobuf._M
         if _storage._requireCoinbaseEmailVerification != rhs_storage._requireCoinbaseEmailVerification {return false}
         if _storage._tipPresets != rhs_storage._tipPresets {return false}
         if _storage._usernameMinBalance != rhs_storage._usernameMinBalance {return false}
+        if _storage._messageEditWindow != rhs_storage._messageEditWindow {return false}
+        if _storage._messageDeleteWindow != rhs_storage._messageDeleteWindow {return false}
         return true
       }
       if !storagesAreEqual {return false}
diff --git a/flipcash2.lock b/flipcash2.lock
index 6f4fdf8..d07c9ab 100644
--- a/flipcash2.lock
+++ b/flipcash2.lock
@@ -1,4 +1,4 @@
 # Pinned upstream contract. Regenerate with scripts/sync-protos.sh <sha>.
 upstream: code-payments/flipcash2-protobuf-api
-commit: 0300d252f35f3524e067aeef22382012c754902a
-subject: Add the ability to set a minimum DM initialization fee (#88)
+commit: 0b56e3cd9a9f380f86a09664f09695a2254d7b0a
+subject: Add message_{edit,delete}_window to UserFlags (#89)
diff --git a/proto/account/v1/flipcash_account_service.proto b/proto/account/v1/flipcash_account_service.proto
index 387a03d..4576274 100644
--- a/proto/account/v1/flipcash_account_service.proto
+++ b/proto/account/v1/flipcash_account_service.proto
@@ -172,6 +172,12 @@ message UserFlags {
 
 	// USDF amount, in quarks, that must be held across all currencies in order to set a username
 	uint64 username_min_balance = 16;
+
+	// Duration after message creation when a message can be edited
+	google.protobuf.Duration message_edit_window = 17;
+
+	// Duration after message creation when a message can be deleted
+	google.protobuf.Duration message_delete_window = 18;
 }
 
 message TipPresets {