diff --git a/ai-docs/ai-migration-v14-v15.md b/ai-docs/ai-migration-v14-v15.md
index 494735538..89d4c92f3 100644
--- a/ai-docs/ai-migration-v14-v15.md
+++ b/ai-docs/ai-migration-v14-v15.md
@@ -117,3 +117,120 @@ dictionary: [`i18n-v15-migration.md`](./i18n-v15-migration.md).
 - **Customize how the preview renders** → provide a `SummarizedMessagePreview` component override (via `ComponentProvider`, or the `<Chat>` / `<Channel>` component props). It receives `SummarizedMessagePreviewProps` (`{ latestMessage, messageDeliveryStatus, participantCount }`).
 - **Preview a specific message** rather than the channel's latest (e.g. a search result previewing the matched message) → pass the new `previewedMessage?: LocalMessage` prop to `ChannelListItem`. It defaults to the channel's reactive latest, `channel.messagePaginator.aggregateState.lastMessage`.
 - **Behavior note:** the preview now honors the channel's `skip_last_msg_update_for_system_msgs` config (a system message no longer becomes the previewed / last message), so the preview and the channel's sort position agree.
+
+## Message UI overrides consolidate on the `MessageUI` slot
+
+The deprecated `Message` component override is removed from `ComponentContext`, and so is every `Message` **prop** that took a message UI component. There is now exactly one way to override the message UI — the `MessageUI` slot — plus `VirtualMessage` for the virtualized list.
+
+| v14                                                                                                                        | v15                                                            |
+| -------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------- |
+| `ComponentContext.Message` (deprecated in v14)                                                                             | `ComponentContext.MessageUI`                                   |
+| `<Message Message={Custom} />`                                                                                             | `MessageUI` override                                           |
+| `<MessageList Message={Custom} />`                                                                                         | `MessageUI` override                                           |
+| `<VirtualizedMessageList Message={Custom} />`                                                                              | `VirtualMessage` override (falls back to `MessageUI`)          |
+| `<Thread Message={Custom} />`                                                                                              | `MessageUI` override, scoped with `WithComponents` (see below) |
+| `additionalMessageListProps` / `additionalVirtualizedMessageListProps` / `additionalParentMessageProps` carrying `Message` | `MessageUI` override                                           |
+
+```tsx
+// before
+<WithComponents overrides={{ Message: CustomMessage }}>
+  <Channel channel={channel}>
+    <MessageList Message={CustomMessage} />
+  </Channel>
+</WithComponents>;
+
+// after
+<WithComponents overrides={{ MessageUI: CustomMessage }}>
+  <Channel channel={channel}>
+    <MessageList />
+  </Channel>
+</WithComponents>;
+```
+
+**`VirtualMessage` still wins inside the virtualized list**, and only there — `VirtualizedMessageList` applies it to its own subtree's `ComponentContext`, so it no longer needs to be drilled through a prop and no longer affects messages rendered outside the list:
+
+```tsx
+<WithComponents
+  overrides={{ MessageUI: CustomMessage, VirtualMessage: CustomVirtualMessage }}
+>
+  <Channel channel={channel}>
+    <VirtualizedMessageList /> {/* renders CustomVirtualMessage */}
+    <MessageList /> {/* renders CustomMessage */}
+  </Channel>
+</WithComponents>
+```
+
+**Overriding only a thread's messages** (was `<Thread Message={…} />`) means scoping the slot to the thread's subtree:
+
+```tsx
+<WithComponents overrides={{ MessageUI: CustomThreadMessage }}>
+  <Thread />
+</WithComponents>
+```
+
+> **This can fail silently in untyped code.** In TypeScript every leftover is a compile error: `Message={…}` on `Message` / `MessageList` / `VirtualizedMessageList` / `Thread` fails with `TS2322`, and a stale `Message:` key in a `WithComponents` `overrides` object or in `additionalMessageListProps` fails with `TS2561` — which reports `Did you mean to write 'MessageUI'?`, so the compiler names the fix. In plain JS or behind an `any`, both are ignored with no warning and the **default** message UI renders. Grep for `Message=` and `Message:` rather than relying on the build to find them.
+
+A custom message UI receives no props — read everything from `useMessageContext()`.
+
+## Context hooks: no `componentName` argument, and required contexts throw
+
+Two changes. The first is a compile break; the second only surfaces at runtime.
+
+### The optional `componentName` argument is removed
+
+```tsx
+// v14
+const { t } = useTranslationContext('EmojiPicker');
+const { textareaRef } = useMessageComposerContext('EmojiPicker');
+
+// v15
+const { t } = useTranslationContext();
+const { textareaRef } = useMessageComposerContext();
+```
+
+Affects `useChatContext`, `useTranslationContext`, `useMessageContext`, `useComponentContext`,
+`useMessageComposerContext`, `useMessageListContext` and `useMessageBounceContext`. TypeScript flags
+every call site (`TS2554`). In plain JS the extra argument is simply ignored — harmless, but dead;
+drop it.
+
+### Required contexts throw outside their provider
+
+In v14 these hooks logged a `console.warn` and returned `{}`, so a component rendered outside its
+provider rendered blank and usually failed later with `Cannot read properties of undefined`. In v15
+the hook throws where the mistake is, naming itself and the provider it needs:
+
+| hook                               | must be rendered within                 |
+| ---------------------------------- | --------------------------------------- |
+| `useChatContext`                   | `<Chat>`                                |
+| `useMessageContext`                | `MessageProvider` (a rendered message)  |
+| `useMessageComposerContext`        | `MessageComposerContextProvider`        |
+| `useMessageListContext`            | `MessageListContextProvider`            |
+| `useVirtualizedMessageListContext` | `VirtualizedMessageListContextProvider` |
+| `useMessageBounceContext`          | `MessageBounceProvider`                 |
+| `usePollContext`                   | `PollProvider`                          |
+| `useDialogManager`                 | `DialogManagerProvider`                 |
+| `useSearchContext`                 | `SearchContextProvider`                 |
+| `useSearchSourceResultsContext`    | `SearchSourceResultsProvider`           |
+| `useContextMenuContext`            | `ContextMenu`                           |
+| `useChannelListItemContext`        | `ChannelListItemUI`                     |
+| `useGalleryContext`                | `Gallery`                               |
+| `useChatViewContext`               | `ChatView`                              |
+
+**What to look for in the app:** any custom component that calls one of these hooks but is mounted
+outside the provider — most often a custom message UI or attachment component rendered outside a
+message, or a component mounted outside `<Chat>` for a loading / empty state. In v14 these rendered
+blank with a console warning; in v15 they throw. Move them inside the provider, or wrap them in it.
+
+These hooks are unchanged and still work outside their provider — no action needed:
+`useTranslationContext` (renders the English copy), `useComponentContext` (empty override map),
+`useChannelInstanceContext`, `useModalContext`, `useAriaLiveAnnouncer` and
+`useMessageTranslationViewContext`.
+
+### Related type changes
+
+- `useChannelInstanceContext()` returns `Partial<ChannelInstanceContextValue>` — `channel` may be
+  `undefined`. Use `useChannel()` when a channel is required; it throws.
+- `ChatViewContext` has no default value, so `useContext(ChatViewContext)` may be `undefined`.
+- `MessageComposerContext` is typed `MessageComposerContextValue | undefined`.
+- The gallery header renders the gallery item's own timestamp and no longer honors the
+  `ComponentContext.MessageTimestamp` override.
diff --git a/examples/tutorial/src/4-custom-ui-components/App.tsx b/examples/tutorial/src/4-custom-ui-components/App.tsx
index 2d4f726a2..e0338a1a3 100644
--- a/examples/tutorial/src/4-custom-ui-components/App.tsx
+++ b/examples/tutorial/src/4-custom-ui-components/App.tsx
@@ -164,7 +164,7 @@ const App = () => {
     <WithComponents
       overrides={{
         ChannelListItemUI: CustomChannelListItem,
-        Message: CustomMessage,
+        MessageUI: CustomMessage,
       }}
     >
       <Chat client={client} theme='custom-theme'>
diff --git a/src/components/Message/Message.tsx b/src/components/Message/Message.tsx
index d34290649..d2062d7be 100644
--- a/src/components/Message/Message.tsx
+++ b/src/components/Message/Message.tsx
@@ -57,7 +57,6 @@ type MessageWithContextProps = Omit<MessageProps, MessagePropsToOmit> &
 
 const MessageWithContext = (props: MessageWithContextProps) => {
   const {
-    Message: propMessage,
     message,
     messageActions = Object.keys(MESSAGE_ACTIONS),
     onUserClick: propOnUserClick,
@@ -68,11 +67,7 @@ const MessageWithContext = (props: MessageWithContextProps) => {
   const channel = useChannel();
   const { isMessageAIGenerated } = useChatContext();
   const channelConfig = useChannelConfig({ cid: channel.cid });
-  const {
-    Message: contextMessage = DefaultMessageUI,
-    // TODO: remove this passthrough once we drop Message from the ComponentContext
-    MessageUI: contextMessageUI = contextMessage,
-  } = useComponentContext();
+  const { MessageUI: MessageUIComponent = DefaultMessageUI } = useComponentContext();
   const { getTranslationView, setTranslationView: setTranslationViewInContext } =
     useMessageTranslationViewContext();
 
@@ -83,7 +78,6 @@ const MessageWithContext = (props: MessageWithContextProps) => {
   );
 
   const actionsEnabled = message.type === 'regular' && message.status === 'received';
-  const MessageUIComponent = propMessage ?? contextMessageUI;
 
   const { onUserClick, onUserHover } = useUserHandler(message, {
     onUserClickHandler: propOnUserClick,
@@ -241,7 +235,6 @@ export const Message = (props: MessageProps) => {
       lastOwnMessage={props.lastOwnMessage}
       lastReceivedId={props.lastReceivedId}
       message={message}
-      Message={props.Message}
       messageActions={props.messageActions}
       messageListRect={props.messageListRect}
       onMentionsClickMessage={onMentionsClick}
diff --git a/src/components/Message/__tests__/Message.test.tsx b/src/components/Message/__tests__/Message.test.tsx
index 342110350..4c5fbf8e0 100644
--- a/src/components/Message/__tests__/Message.test.tsx
+++ b/src/components/Message/__tests__/Message.test.tsx
@@ -160,7 +160,9 @@ async function renderComponent({
       <Channel channel={channel}>
         <WithComponents
           overrides={{
-            Message: () => <CustomMessageUIComponent contextCallback={contextCallback} />,
+            MessageUI: () => (
+              <CustomMessageUIComponent contextCallback={contextCallback} />
+            ),
             reactionOptions: defaultReactionOptions,
             ...components,
           }}
@@ -877,7 +879,7 @@ describe('<Message /> component', () => {
     const UIMock = vi.fn(() => <div>UI mock</div>);
 
     const { rerender } = await renderComponent({
-      components: { Message: UIMock },
+      components: { MessageUI: UIMock },
       message,
     });
 
@@ -886,7 +888,7 @@ describe('<Message /> component', () => {
     UIMock.mockClear();
 
     await renderComponent({
-      components: { Message: UIMock },
+      components: { MessageUI: UIMock },
       message: updatedMessage,
       renderer: rerender,
     });
@@ -899,7 +901,7 @@ describe('<Message /> component', () => {
     const UIMock = vi.fn(() => <div>UI mock</div>);
 
     const { rerender } = await renderComponent({
-      components: { Message: UIMock },
+      components: { MessageUI: UIMock },
       message,
     });
 
@@ -907,7 +909,7 @@ describe('<Message /> component', () => {
     UIMock.mockClear();
 
     await renderComponent({
-      components: { Message: UIMock },
+      components: { MessageUI: UIMock },
       message,
       props: { readBy: [bob] },
       renderer: rerender,
@@ -921,7 +923,7 @@ describe('<Message /> component', () => {
     const UIMock = vi.fn(() => <div>UI mock</div>);
 
     const { rerender } = await renderComponent({
-      components: { Message: UIMock },
+      components: { MessageUI: UIMock },
       message,
       props: { groupStyles: ['bottom'] },
     });
@@ -930,7 +932,7 @@ describe('<Message /> component', () => {
     UIMock.mockClear();
 
     await renderComponent({
-      components: { Message: UIMock },
+      components: { MessageUI: UIMock },
       message,
       props: { groupStyles: ['bottom', 'left'] as any },
       renderer: rerender,
@@ -944,7 +946,7 @@ describe('<Message /> component', () => {
     const UIMock = vi.fn(() => <div>UI mock</div>);
 
     const { rerender } = await renderComponent({
-      components: { Message: UIMock },
+      components: { MessageUI: UIMock },
       message,
       props: { lastReceivedId: 'last-received-id-1' },
     });
@@ -953,7 +955,7 @@ describe('<Message /> component', () => {
     UIMock.mockClear();
 
     await renderComponent({
-      components: { Message: UIMock },
+      components: { MessageUI: UIMock },
       message,
       props: { lastReceivedId: 'last-received-id-2' },
       renderer: rerender,
@@ -967,7 +969,7 @@ describe('<Message /> component', () => {
     const UIMock = vi.fn(() => <div>UI mock</div>);
 
     const { rerender } = await renderComponent({
-      components: { Message: UIMock },
+      components: { MessageUI: UIMock },
       message,
       props: {
         messageListRect: fromPartial<DOMRect>({
@@ -983,7 +985,7 @@ describe('<Message /> component', () => {
     UIMock.mockClear();
 
     await renderComponent({
-      components: { Message: UIMock },
+      components: { MessageUI: UIMock },
       message,
       props: {
         messageListRect: fromPartial<DOMRect>({
diff --git a/src/components/Message/__tests__/MessageText.test.tsx b/src/components/Message/__tests__/MessageText.test.tsx
index f41651be6..9399636c4 100644
--- a/src/components/Message/__tests__/MessageText.test.tsx
+++ b/src/components/Message/__tests__/MessageText.test.tsx
@@ -96,7 +96,7 @@ async function renderMessageText({ customProps = {} } = {}) {
             value={mockComponentContext({
               Attachment,
 
-              Message: () => <MessageUI />,
+              MessageUI: () => <MessageUI />,
               reactionOptions: defaultReactionOptions,
             })}
           >
diff --git a/src/components/Message/__tests__/MessageUI.test.tsx b/src/components/Message/__tests__/MessageUI.test.tsx
index b36e36331..22f8872d7 100644
--- a/src/components/Message/__tests__/MessageUI.test.tsx
+++ b/src/components/Message/__tests__/MessageUI.test.tsx
@@ -170,7 +170,7 @@ describe('<MessageSimple />', () => {
             <WithComponents
               overrides={{
                 Attachment: AttachmentMock,
-                Message: () => <MessageUI {...props} />,
+                MessageUI: () => <MessageUI {...props} />,
                 reactionOptions: defaultReactionOptions,
                 ...components,
               }}
diff --git a/src/components/Message/__tests__/QuotedMessage.test.tsx b/src/components/Message/__tests__/QuotedMessage.test.tsx
index df2254a1f..ccde81aa2 100644
--- a/src/components/Message/__tests__/QuotedMessage.test.tsx
+++ b/src/components/Message/__tests__/QuotedMessage.test.tsx
@@ -76,7 +76,7 @@ async function renderQuotedMessage({
         >
           <ComponentProvider
             value={mockComponentContext({
-              Message: () => <MessageUI />,
+              MessageUI: () => <MessageUI />,
               ...componentContext,
             })}
           >
diff --git a/src/components/Message/types.ts b/src/components/Message/types.ts
index 80a046d9f..1ac688a7d 100644
--- a/src/components/Message/types.ts
+++ b/src/components/Message/types.ts
@@ -7,7 +7,6 @@ import type { MessageActionsArray } from './utils';
 import type { GroupStyle } from '../MessageList/utils';
 import type { MessageComposerProps } from '../MessageComposer';
 import type { ReactionsComparator } from '../Reactions/types';
-import type { ComponentContextValue } from '../../context/ComponentContext';
 import type { MessageContextValue } from '../../context/MessageContext';
 import type { RenderTextFunction } from './renderText';
 
@@ -41,10 +40,6 @@ export type MessageProps = {
   // todo: could be moved to the Channel instance reactive state as lastReceivedMessage keeping the the receipt status as well (useful for channel preview)
   /** Latest message id on current channel */
   lastReceivedId?: string | null;
-  /** UI component to display a Message in MessageList, overrides value in [ComponentContext](https://getstream.io/chat/docs/sdk/react/contexts/component_context/#message)
-   * @deprecated use `ComponentContext` (`WithComponents`) component override instead (`MessageUI` slot)
-   */
-  Message?: ComponentContextValue['MessageUI'];
   /** Array of allowed message actions (ex: ['edit', 'delete', 'flag', 'mute', 'pin', 'quote', 'react', 'reply']). To disable all actions, provide an empty array. */
   messageActions?: MessageActionsArray;
   /** DOMRect object for parent MessageList component */
diff --git a/src/components/Message/utils.tsx b/src/components/Message/utils.tsx
index b9b665f16..830c6836f 100644
--- a/src/components/Message/utils.tsx
+++ b/src/components/Message/utils.tsx
@@ -208,11 +208,11 @@ export const areMessagePropsEqual = (
     showDetailedReactions?: boolean;
   },
 ) => {
-  const { message: prevMessage, Message: prevMessageUI } = prevProps;
-  const { message: nextMessage, Message: nextMessageUI } = nextProps;
-
-  if (prevMessageUI !== nextMessageUI) return false;
+  const { message: prevMessage } = prevProps;
+  const { message: nextMessage } = nextProps;
 
+  // The message UI component itself is not compared here: it is resolved from
+  // `ComponentContext`, and context updates re-render consumers regardless of `React.memo`.
   if (nextProps.showDetailedReactions !== prevProps.showDetailedReactions) {
     return false;
   }
diff --git a/src/components/MessageList/MessageList.tsx b/src/components/MessageList/MessageList.tsx
index 0c65a42bb..e53e72bb6 100644
--- a/src/components/MessageList/MessageList.tsx
+++ b/src/components/MessageList/MessageList.tsx
@@ -211,7 +211,6 @@ const MessageListWithContext = (props: MessageListWithContextProps) => {
       closeReactionSelectorOnClick: props.closeReactionSelectorOnClick,
       disableQuotedMessages: props.disableQuotedMessages,
       formatDate: props.formatDate,
-      Message: props.Message,
       messageActions,
       messageListRect: wrapperRect,
       onMentionsClick: props.onMentionsClick,
@@ -439,7 +438,6 @@ type PropsDrilledToMessage =
   | 'closeReactionSelectorOnClick'
   | 'disableQuotedMessages'
   | 'formatDate'
-  | 'Message'
   | 'messageActions'
   | 'onMentionsClick'
   | 'onMentionsHover'
diff --git a/src/components/MessageList/VirtualizedMessageList.tsx b/src/components/MessageList/VirtualizedMessageList.tsx
index 195715e03..48d407b10 100644
--- a/src/components/MessageList/VirtualizedMessageList.tsx
+++ b/src/components/MessageList/VirtualizedMessageList.tsx
@@ -33,8 +33,7 @@ import { NewMessageNotification as DefaultNewMessageNotification } from './NewMe
 import { MessageListMainPanel as DefaultMessageListMainPanel } from './MessageListMainPanel';
 import type { GroupStyle, ProcessMessagesParams, RenderedMessage } from './utils';
 import { getGroupStyles, getLastReceived, processMessages } from './utils';
-import type { MessageProps, MessageUIComponentProps } from '../Message';
-import { MessageUI } from '../Message';
+import type { MessageProps } from '../Message';
 import { UnreadMessagesNotification as DefaultUnreadMessagesNotification } from './UnreadMessagesNotification';
 import {
   calculateFirstItemIndex,
@@ -53,7 +52,7 @@ import {
 import { DateSeparator as DefaultDateSeparator } from '../DateSeparator';
 import { EventComponent as DefaultMessageSystem } from '../EventComponent';
 
-import { DialogManagerProvider, useChannel } from '../../context';
+import { DialogManagerProvider, useChannel, WithComponents } from '../../context';
 import type { ChatContextValue } from '../../context/ChatContext';
 import { useChatContext } from '../../context/ChatContext';
 import type { ComponentContextValue } from '../../context/ComponentContext';
@@ -93,7 +92,6 @@ type VirtualizedMessageListPropsForContext =
   | 'customMessageRenderer'
   | 'head'
   // | 'loadingMore'
-  | 'Message'
   | 'returnAllReadData'
   | 'shouldGroupByUser';
 
@@ -227,7 +225,6 @@ const VirtualizedMessageListWithContext = (
     // loadMore,
     // loadMoreNewer,
     maxTimeBetweenGroupedMessages,
-    Message: MessageUIComponentFromProps,
     messageActions,
     // messageLimit = DEFAULT_NEXT_CHANNEL_PAGE_SIZE,
     // messages,
@@ -272,9 +269,15 @@ const VirtualizedMessageListWithContext = (
     TypingIndicator,
     UnreadMessagesNotification = DefaultUnreadMessagesNotification,
     UnreadMessagesSeparator = DefaultUnreadMessagesSeparator,
-    VirtualMessage: MessageUIComponentFromContext = MessageUI,
+    VirtualMessage,
   } = useComponentContext();
-  const MessageUIComponent = MessageUIComponentFromProps || MessageUIComponentFromContext;
+  // `VirtualMessage` overrides `MessageUI` for the messages this list renders, so it is
+  // applied to this subtree's `ComponentContext` rather than drilled down to each `Message`.
+  // Memoized so the provider does not hand every consumer below a new value each render.
+  const virtualMessageOverrides = useMemo(
+    () => ({ MessageUI: VirtualMessage }),
+    [VirtualMessage],
+  );
 
   const { client, customClasses } = useChatContext();
   const messagePaginator = useMessagePaginator();
@@ -531,7 +534,7 @@ const VirtualizedMessageListWithContext = (
     ? `virtualized-message-list-dialog-manager-thread-${id}`
     : `virtualized-message-list-dialog-manager-${id}`;
 
-  return (
+  const list = (
     <VirtualizedMessageListContextProvider value={{ scrollToBottom }}>
       <MessageTranslationViewProvider>
         <MessageListMainPanel>
@@ -580,7 +583,6 @@ const VirtualizedMessageListWithContext = (
                   lastReadMessageId: channelUnreadUiState?.lastReadMessageId,
                   lastReceivedMessageId,
                   loadingMore: isLoading,
-                  Message: MessageUIComponent,
                   messageActions,
                   messageGroupStyles,
                   MessageSystem,
@@ -648,6 +650,13 @@ const VirtualizedMessageListWithContext = (
       </MessageTranslationViewProvider>
     </VirtualizedMessageListContextProvider>
   );
+
+  // Only wrap when there is something to override, so the common case adds no provider.
+  return VirtualMessage ? (
+    <WithComponents overrides={virtualMessageOverrides}>{list}</WithComponents>
+  ) : (
+    list
+  );
 };
 
 export type VirtualizedMessageListProps = Partial<
@@ -699,8 +708,6 @@ export type VirtualizedMessageListProps = Partial<
   // loadMoreNewer?: () => Promise<void>;
   /** Maximum time in milliseconds that should occur between messages to still consider them grouped together */
   maxTimeBetweenGroupedMessages?: number;
-  /** Custom UI component to display a message, defaults to and accepts same props as [MessageSimple](https://github.com/GetStream/stream-chat-react/blob/master/src/components/Message/MessageSimple.tsx) */
-  Message?: React.ComponentType<MessageUIComponentProps>;
   // /** The limit to use when paginating messages */
   // messageLimit?: number;
   /** Optional prop to override the messages available from the active message paginator. */
diff --git a/src/components/MessageList/VirtualizedMessageListComponents.tsx b/src/components/MessageList/VirtualizedMessageListComponents.tsx
index 4c4eeb747..3f5233d03 100644
--- a/src/components/MessageList/VirtualizedMessageListComponents.tsx
+++ b/src/components/MessageList/VirtualizedMessageListComponents.tsx
@@ -118,7 +118,6 @@ export const messageRenderer = (
     lastReadDate,
     lastReadMessageId,
     lastReceivedMessageId,
-    Message: MessageUIComponent,
     messageActions,
     messageGroupStyles,
     MessageSystem,
@@ -185,7 +184,6 @@ export const messageRenderer = (
         lastOwnMessage={lastOwnMessage}
         lastReceivedId={lastReceivedMessageId}
         message={message}
-        Message={MessageUIComponent}
         messageActions={messageActions}
         reactionDetailsSort={reactionDetailsSort}
         readBy={ownMessagesReadByOthers[message.id] || []}
diff --git a/src/components/MessageList/__tests__/MessageList.test.tsx b/src/components/MessageList/__tests__/MessageList.test.tsx
index c081862bd..13dc2e28d 100644
--- a/src/components/MessageList/__tests__/MessageList.test.tsx
+++ b/src/components/MessageList/__tests__/MessageList.test.tsx
@@ -1679,7 +1679,7 @@ describe('MessageList', () => {
     });
   });
 
-  describe('props forwarded to Message', () => {
+  describe('MessageUI override', () => {
     it.each([[true], [false]])(
       'invokes handleMarkUnread from Message context (shouldFail: %s)',
       async (shouldFail) => {
@@ -1687,7 +1687,7 @@ describe('MessageList', () => {
         if (shouldFail) markUnreadSpy.mockRejectedValueOnce(undefined!);
 
         const message = generateMessage();
-        const Message = () => {
+        const MessageUI = () => {
           const { handleMarkUnread } = useMessageContext();
           useEffect(() => {
             const event = fromPartial<React.BaseSyntheticEvent>({
@@ -1702,7 +1702,8 @@ describe('MessageList', () => {
           renderComponent({
             channelProps: { channel },
             chatClient,
-            msgListProps: { Message, messages: [message] },
+            components: { MessageUI },
+            msgListProps: { messages: [message] },
           });
         });
 
diff --git a/src/components/MessageList/__tests__/VirtualizedMessageList.test.tsx b/src/components/MessageList/__tests__/VirtualizedMessageList.test.tsx
index 7cbddcec1..55c5d39e8 100644
--- a/src/components/MessageList/__tests__/VirtualizedMessageList.test.tsx
+++ b/src/components/MessageList/__tests__/VirtualizedMessageList.test.tsx
@@ -17,6 +17,7 @@ import { VirtualizedMessageList } from '../VirtualizedMessageList';
 
 import { Chat } from '../../Chat';
 import { Channel } from '../../Channel';
+import { useComponentContext, WithComponents } from '../../../context';
 
 vi.mock('react-virtuoso', async () => {
   const { Virtuoso } = await import('react-virtuoso');
@@ -99,6 +100,81 @@ describe('VirtualizedMessageList', () => {
     });
     expect(result.container).toMatchSnapshot();
   });
+
+  // The `VirtualMessage` override has to beat `MessageUI`, but only for messages rendered
+  // by this list. The list applies it by overriding `MessageUI` for its own subtree, so
+  // these assert on what `useComponentContext()` resolves to inside vs. outside the list.
+  // Virtuoso renders no items under jsdom (it measures document height), so `head` is the
+  // in-subtree render point available to us — it is the same provider subtree the items
+  // render into.
+  describe('VirtualMessage override', () => {
+    const CustomMessageUI = () => <div />;
+    const CustomVirtualMessage = () => <div />;
+
+    const ResolvedMessageUIProbe = ({ label }: { label: string }) => {
+      const { MessageUI } = useComponentContext();
+      return (
+        <div
+          data-probe={label}
+          data-resolved={(MessageUI as { name?: string } | undefined)?.name ?? 'none'}
+        />
+      );
+    };
+
+    const resolvedAt = (container: HTMLElement, label: string) =>
+      container.querySelector(`[data-probe="${label}"]`)?.getAttribute('data-resolved') ??
+      null;
+
+    const renderWithOverrides = async (
+      overrides: Parameters<typeof WithComponents>[0]['overrides'],
+    ) => {
+      const { channel, client } = await createChannel();
+      vi.mocked(nanoid).mockReturnValue('mockedId');
+
+      let result: RenderResult;
+      await act(() => {
+        result = render(
+          <Chat client={client}>
+            <Channel channel={channel}>
+              <WithComponents overrides={overrides}>
+                <ResolvedMessageUIProbe label='outside' />
+                <VirtualizedMessageList
+                  head={<ResolvedMessageUIProbe label='inside' />}
+                />
+              </WithComponents>
+            </Channel>
+          </Chat>,
+        );
+      });
+
+      return result!.container;
+    };
+
+    it('takes precedence over MessageUI for messages rendered by the list', async () => {
+      const container = await renderWithOverrides({
+        MessageUI: CustomMessageUI,
+        VirtualMessage: CustomVirtualMessage,
+      });
+
+      expect(resolvedAt(container, 'inside')).toBe('CustomVirtualMessage');
+    });
+
+    it('does not leak outside the list', async () => {
+      const container = await renderWithOverrides({
+        MessageUI: CustomMessageUI,
+        VirtualMessage: CustomVirtualMessage,
+      });
+
+      expect(resolvedAt(container, 'outside')).toBe('CustomMessageUI');
+    });
+
+    it('leaves the MessageUI override in place when unset', async () => {
+      const container = await renderWithOverrides({ MessageUI: CustomMessageUI });
+
+      expect(resolvedAt(container, 'inside')).toBe('CustomMessageUI');
+      expect(resolvedAt(container, 'outside')).toBe('CustomMessageUI');
+    });
+  });
 });
 
 describe('usePrependedMessagesCount', () => {
diff --git a/src/components/MessageList/__tests__/VirtualizedMessageListComponents.test.tsx b/src/components/MessageList/__tests__/VirtualizedMessageListComponents.test.tsx
index e88ab196c..37c3cd9d7 100644
--- a/src/components/MessageList/__tests__/VirtualizedMessageListComponents.test.tsx
+++ b/src/components/MessageList/__tests__/VirtualizedMessageListComponents.test.tsx
@@ -321,7 +321,7 @@ describe('VirtualizedMessageComponents', () => {
       it('should forward message group styles', () => {
         const virtuosoRef = { current: {} };
         let groupStylesMessageContext: GroupStyle[];
-        const Message = () => {
+        const GroupStylesProbe = () => {
           const { groupStyles } = useMessageContext();
           groupStylesMessageContext = groupStyles;
           return null;
@@ -332,7 +332,6 @@ describe('VirtualizedMessageComponents', () => {
           <>
             {processedMessages.map((_, numItemsPrepended) => {
               const virtuosoContext = {
-                Message,
                 messageGroupStyles,
                 numItemsPrepended,
                 ownMessagesDeliveredToOthers: {},
@@ -352,6 +351,7 @@ describe('VirtualizedMessageComponents', () => {
               );
             })}
           </>,
+          { MessageUI: GroupStylesProbe },
         );
         expect(groupStylesMessageContext).toStrictEqual([
           messageGroupStyles[processedMessages[0].id],
@@ -466,7 +466,7 @@ describe('VirtualizedMessageComponents', () => {
           }),
         );
 
-        const Message = () => <div className='message-component' />;
+        const MessageUI = () => <div className='message-component' />;
 
         const renderMarkUnread = async ({
           virtuosoContext,
@@ -491,7 +491,7 @@ describe('VirtualizedMessageComponents', () => {
             result = render(
               <Chat client={markUnreadClient}>
                 <ChannelComponent channel={markUnreadChannel}>
-                  <ComponentProvider value={mockComponentContext()}>
+                  <ComponentProvider value={mockComponentContext({ MessageUI })}>
                     {messageRenderer(virtuosoIndex ?? PREPEND_OFFSET, undefined, ctx)}
                   </ComponentProvider>
                 </ChannelComponent>
@@ -507,7 +507,6 @@ describe('VirtualizedMessageComponents', () => {
               lastReadDate: new Date(messages[0].created_at),
               lastReadMessageId: messages[0].id,
               lastReceivedMessageId: messages[1].id,
-              Message,
               messageGroupStyles: {},
               numItemsPrepended: 1,
               ownMessagesDeliveredToOthers: {},
@@ -533,7 +532,6 @@ describe('VirtualizedMessageComponents', () => {
               lastReadDate: new Date(messages[1].created_at),
               lastReadMessageId: messages[1].id,
               lastReceivedMessageId: messages[1].id,
-              Message,
               messageGroupStyles: {},
               numItemsPrepended: 1,
               ownMessagesDeliveredToOthers: {},
@@ -560,7 +558,6 @@ describe('VirtualizedMessageComponents', () => {
               firstUnreadMessageId: messages[1].id,
               lastReadMessageId: messages[0].id,
               lastReceivedMessageId: messages[1].id,
-              Message,
               messageGroupStyles: {},
               numItemsPrepended: 1,
               ownMessagesDeliveredToOthers: {},
@@ -582,7 +579,6 @@ describe('VirtualizedMessageComponents', () => {
             virtuosoContext: {
               lastReadMessageId: messages[0].id,
               lastReceivedMessageId: messages[1].id,
-              Message,
               messageGroupStyles: {},
               numItemsPrepended: 1,
               ownMessagesDeliveredToOthers: {},
@@ -604,7 +600,6 @@ describe('VirtualizedMessageComponents', () => {
             virtuosoContext: {
               lastReadMessageId: messages[0].id,
               lastReceivedMessageId: messages[1].id,
-              Message,
               messageGroupStyles: {},
               numItemsPrepended: 0,
               ownMessagesDeliveredToOthers: {},
@@ -664,7 +659,6 @@ describe('VirtualizedMessageComponents', () => {
             <>
               {processedMessages.map((_, numItemsPrepended) => {
                 const virtuosoContext = {
-                  Message: MessageUI,
                   messageGroupStyles,
                   numItemsPrepended,
                   ownMessagesDeliveredToOthers: {},
@@ -685,6 +679,7 @@ describe('VirtualizedMessageComponents', () => {
                 );
               })}
             </>,
+            { MessageUI },
           );
           const messageElements = container.querySelectorAll('.str-chat__message');
 
diff --git a/src/components/Thread/Thread.tsx b/src/components/Thread/Thread.tsx
index b7c4b5f99..c35368c78 100644
--- a/src/components/Thread/Thread.tsx
+++ b/src/components/Thread/Thread.tsx
@@ -20,7 +20,7 @@ import { useThreadContext } from '../Threads';
 import { useStateStore } from '../../store';
 import { useThreadRequestHandlers } from './hooks/useThreadRequestHandlers';
 
-import type { MessageProps, MessageUIComponentProps } from '../Message/types';
+import type { MessageProps } from '../Message/types';
 import type { MessageActionsArray } from '../Message/utils';
 import type {
   DeleteMessageOptions,
@@ -52,8 +52,6 @@ export type ThreadProps = {
   autoFocus?: boolean;
   /** Injects date separator components into `Thread`, defaults to `false`. To be passed to the underlying `MessageList` or `VirtualizedMessageList` components */
   enableDateSeparator?: boolean;
-  /** Custom thread message UI component used to override the default `Message` value stored in `ComponentContext` */
-  Message?: React.ComponentType<MessageUIComponentProps>;
   /** Array of allowed message actions (ex: ['edit', 'delete', 'flag', 'mute', 'pin', 'quote', 'react', 'reply']). To disable all actions, provide an empty array. */
   messageActions?: MessageActionsArray;
   /** Custom action handler to override the default `client.deleteMessage(message.id)` function in thread flows */
@@ -137,18 +135,13 @@ const ThreadInner = (props: ThreadProps & { key: string }) => {
     doSendMessageRequest,
     doUpdateMessageRequest,
     enableDateSeparator = false,
-    Message: PropMessage,
     messageActions = Object.keys(MESSAGE_ACTIONS),
     virtualized,
   } = props;
   const threadInstance = useThreadContext();
   const { client, customClasses } = useChatContext();
-  const {
-    Message: ContextMessage,
-    ThreadHead = DefaultThreadHead,
-    ThreadHeader = DefaultThreadHeader,
-    VirtualMessage,
-  } = useComponentContext();
+  const { ThreadHead = DefaultThreadHead, ThreadHeader = DefaultThreadHeader } =
+    useComponentContext();
 
   const { isStateStale, parentMessage } =
     useStateStore(threadInstance?.state, selector) ?? {};
@@ -176,10 +169,8 @@ const ThreadInner = (props: ThreadProps & { key: string }) => {
     threadInstance?.deactivate();
   }, [closeThreadPanel, threadInstance]);
 
-  const ThreadMessage = PropMessage || additionalMessageListProps?.Message;
-  const FallbackMessage = virtualized && VirtualMessage ? VirtualMessage : ContextMessage;
-  const MessageUIComponent = ThreadMessage || FallbackMessage;
-
+  // The thread message UI comes from `ComponentContext` (`MessageUI`, or `VirtualMessage`
+  // which the virtualized list applies to its own subtree), so nothing is resolved here.
   const ThreadMessageList = virtualized ? VirtualizedMessageList : MessageList;
   useThreadRequestHandlers({
     doDeleteMessageRequest,
@@ -244,7 +235,6 @@ const ThreadInner = (props: ThreadProps & { key: string }) => {
     <ThreadHead
       key={parentMessage.id}
       message={parentMessage}
-      Message={MessageUIComponent}
       {...additionalParentMessageProps}
     />
   );
@@ -265,7 +255,6 @@ const ThreadInner = (props: ThreadProps & { key: string }) => {
           <ThreadMessageList
             disableDateSeparator={!enableDateSeparator}
             head={head}
-            Message={MessageUIComponent}
             messageActions={messageActions}
             {...(virtualized
               ? additionalVirtualizedMessageListProps
diff --git a/src/components/Thread/__tests__/Thread.test.tsx b/src/components/Thread/__tests__/Thread.test.tsx
index 7066255bc..f5eda965c 100644
--- a/src/components/Thread/__tests__/Thread.test.tsx
+++ b/src/components/Thread/__tests__/Thread.test.tsx
@@ -19,7 +19,6 @@ import {
   mockComponentContext,
 } from '../../../mock-builders';
 
-import { Message as MessageMock } from '../../Message/Message';
 import { MessageComposer as MessageInputMock } from '../../MessageComposer/MessageComposer';
 import { MessageList as MessageListMock } from '../../MessageList';
 import { Thread } from '../Thread';
@@ -138,12 +137,7 @@ describe('Thread', () => {
     const additionalMessageListProps = {
       loadingMore: false,
     };
-    renderComponent({
-      threadProps: {
-        additionalMessageListProps,
-        Message: MessageMock as ThreadProps['Message'],
-      },
-    });
+    renderComponent({ threadProps: { additionalMessageListProps } });
 
     expect(MessageListMock).toHaveBeenCalledWith(
       expect.objectContaining({
@@ -151,7 +145,6 @@ describe('Thread', () => {
         head: expect.objectContaining({
           type: expect.objectContaining({ name: 'ThreadHead' }),
         }),
-        Message: MessageMock,
         messageActions: expect.any(Array),
         ...additionalMessageListProps,
       }),
@@ -164,11 +157,7 @@ describe('Thread', () => {
       loadingMore: false,
     };
     renderComponent({
-      threadProps: {
-        additionalMessageListProps,
-        enableDateSeparator: true,
-        Message: MessageMock as ThreadProps['Message'],
-      },
+      threadProps: { additionalMessageListProps, enableDateSeparator: true },
     });
 
     expect(MessageListMock).toHaveBeenCalledWith(
@@ -177,7 +166,6 @@ describe('Thread', () => {
         head: expect.objectContaining({
           type: expect.objectContaining({ name: 'ThreadHead' }),
         }),
-        Message: MessageMock,
         messageActions: expect.any(Array),
         ...additionalMessageListProps,
       }),
diff --git a/src/context/ComponentContext.tsx b/src/context/ComponentContext.tsx
index ea58d9ee5..0b821a4dd 100644
--- a/src/context/ComponentContext.tsx
+++ b/src/context/ComponentContext.tsx
@@ -180,10 +180,6 @@ export type ComponentContextValue = {
   ProgressIndicator?: React.ComponentType<ProgressIndicatorProps>;
   /** Custom UI component to display a message in the standard `MessageList`, defaults to and accepts the same props as: [MessageUI](https://github.com/GetStream/stream-chat-react/blob/master/src/components/Message/MessageUI.tsx) */
   MessageUI?: React.ComponentType<MessageUIComponentProps>;
-  /** Custom UI component to display a message in the standard `MessageList`, defaults to and accepts the same props as: [MessageUI](https://github.com/GetStream/stream-chat-react/blob/master/src/components/Message/MessageUI.tsx)
-   * @deprecated use `MessageUI` instead
-   */
-  Message?: React.ComponentType<MessageUIComponentProps>;
   /** Custom UI component for message actions popup, accepts no props, all the defaults are set within [MessageActions (unstable)](https://github.com/GetStream/stream-chat-react/blob/master/src/experimental/MessageActions/MessageActions.tsx) */
   MessageActions?: React.ComponentType;
   /** Custom UI component to display the contents of a bounced message modal. Usually it allows to retry, edit, or delete the message. Defaults to and accepts the same props as: [MessageBouncePrompt](https://github.com/GetStream/stream-chat-react/blob/master/src/components/MessageBounce/MessageBouncePrompt.tsx) */
diff --git a/src/context/WithComponents.tsx b/src/context/WithComponents.tsx
index 4f67a0da7..621d6fcb0 100644
--- a/src/context/WithComponents.tsx
+++ b/src/context/WithComponents.tsx
@@ -1,4 +1,4 @@
-import React, { useContext } from 'react';
+import React, { useContext, useMemo } from 'react';
 import type { PropsWithChildren } from 'react';
 
 import { ComponentContext } from './ComponentContext';
@@ -9,7 +9,14 @@ export function WithComponents({
   overrides,
 }: PropsWithChildren<{ overrides: Partial<ComponentContextValue> }>) {
   const parentOverrides = useContext(ComponentContext);
-  const actualOverrides: ComponentContextValue = { ...parentOverrides, ...overrides };
+  // Memoized because this provider sits on render paths hot enough for the identity of the
+  // merged value to matter: a new object on every render re-renders every
+  // `useComponentContext()` consumer below it, which would defeat the per-message
+  // memoization in `areMessagePropsEqual`.
+  const actualOverrides: ComponentContextValue = useMemo(
+    () => ({ ...parentOverrides, ...overrides }),
+    [parentOverrides, overrides],
+  );
   return (
     <ComponentContext.Provider value={actualOverrides}>
       {children}