diff --git a/extensions/notebook-renderers/src/index.ts b/extensions/notebook-renderers/src/index.ts
index df674353633..0450aa54f10 100644
--- a/extensions/notebook-renderers/src/index.ts
+++ b/extensions/notebook-renderers/src/index.ts
@@ -265,12 +265,20 @@ function scrollingEnabled(output: OutputItem, options: RenderOptions) {
 		metadata.scrollable : options.outputScrolling;
 }
 
+interface OutputWithAppend extends OutputItem {
+	appendedText?(): string | undefined;
+}
+
 //  div.cell_container
 //    div.output_container
 //      div.output.output-stream		<-- outputElement parameter
 //        div.scrollable? tabindex="0" 	<-- contentParent
 //          div output-item-id="{guid}"	<-- content from outputItem parameter
-function renderStream(outputInfo: OutputItem, outputElement: HTMLElement, error: boolean, ctx: IRichRenderContext): IDisposable {
+function renderStream(outputInfo: OutputWithAppend, outputElement: HTMLElement, error: boolean, ctx: IRichRenderContext): IDisposable {
+	const appendedText = outputInfo.appendedText?.();
+	if (appendedText) {
+		console.log(`appending output version ${appendedText}`);
+	}
 	const disposableStore = createDisposableStore();
 	const outputScrolling = scrollingEnabled(outputInfo, ctx.settings);
 
@@ -301,6 +309,9 @@ function renderStream(outputInfo: OutputItem, outputElement: HTMLElement, error:
 		const existingContent = outputElement.querySelector(`[output-item-id="${outputInfo.id}"]`) as HTMLElement | null;
 		let contentParent = existingContent?.parentElement;
 		if (existingContent && contentParent) {
+			if (appendedText){
+				existingContent
+			}
 			existingContent.replaceWith(newContent);
 			while (newContent.nextSibling) {
 				// clear out any stale content if we had previously combined streaming outputs into this one
diff --git a/src/vs/workbench/api/common/extHostNotebookDocument.ts b/src/vs/workbench/api/common/extHostNotebookDocument.ts
index 6f48147c9e4..e8970f70dee 100644
--- a/src/vs/workbench/api/common/extHostNotebookDocument.ts
+++ b/src/vs/workbench/api/common/extHostNotebookDocument.ts
@@ -132,7 +132,7 @@ export class ExtHostCell {
 					const compressed = notebookCommon.compressOutputItemStreams(mimeOutputs.get(mime)!);
 					output.items.push({
 						mime,
-						data: compressed.buffer
+						data: compressed.data.buffer
 					});
 				});
 			}
diff --git a/src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts b/src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts
index 0fdc7c3c612..4e3b2573ec3 100644
--- a/src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts
+++ b/src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts
@@ -1506,6 +1506,8 @@ export class BackLayerWebView<T extends ICommonCellInfo> extends Themable {
 		if (content.type === RenderOutputType.Extension) {
 			const output = content.source.model;
 			const firstBuffer = output.outputs.find(op => op.mime === content.mimeType)!;
+			const appenededData = output.appendedSinceVersion(outputCache.versionId, content.mimeType);
+			const appended = appenededData ? { valueBytes: appenededData.buffer, previousVersion: outputCache.versionId } : undefined;
 
 			const valueBytes = copyBufferIfNeeded(firstBuffer.data.buffer, transfer);
 			updatedContent = {
@@ -1515,6 +1517,7 @@ export class BackLayerWebView<T extends ICommonCellInfo> extends Themable {
 				output: {
 					mime: content.mimeType,
 					valueBytes,
+					appended: appended
 				},
 				allOutputs: output.outputs.map(output => ({ mime: output.mime }))
 			};
diff --git a/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewMessages.ts b/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewMessages.ts
index 15fc1f19790..1927f9497dc 100644
--- a/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewMessages.ts
+++ b/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewMessages.ts
@@ -188,11 +188,18 @@ export interface IOutputRequestDto {
 export interface OutputItemEntry {
 	readonly mime: string;
 	readonly valueBytes: Uint8Array;
+	readonly appended?: { valueBytes: Uint8Array; previousVersion: number };
 }
 
 export type ICreationContent =
 	| { readonly type: RenderOutputType.Html; readonly htmlContent: string }
-	| { readonly type: RenderOutputType.Extension; readonly outputId: string; readonly metadata: unknown; readonly output: OutputItemEntry; readonly allOutputs: ReadonlyArray<{ readonly mime: string }> };
+	| {
+		readonly type: RenderOutputType.Extension;
+		readonly outputId: string;
+		readonly metadata: unknown;
+		readonly output: OutputItemEntry;
+		readonly allOutputs: ReadonlyArray<{ readonly mime: string }>;
+	};
 
 export interface ICreationRequestMessage {
 	readonly type: 'html';
diff --git a/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewPreloads.ts b/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewPreloads.ts
index 25dab44de71..190980671a0 100644
--- a/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewPreloads.ts
+++ b/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewPreloads.ts
@@ -804,6 +804,7 @@ async function webviewPreloads(ctx: PreloadContext) {
 
 	interface ExtendedOutputItem extends rendererApi.OutputItem {
 		readonly _allOutputItems: ReadonlyArray<AdditionalOutputItemInfo>;
+		appendedText?(): string | undefined;
 	}
 
 	let hasWarnedAboutAllOutputItemsProposal = false;
@@ -813,7 +814,8 @@ async function webviewPreloads(ctx: PreloadContext) {
 		mime: string,
 		metadata: unknown,
 		valueBytes: Uint8Array,
-		allOutputItemData: ReadonlyArray<{ readonly mime: string }>
+		allOutputItemData: ReadonlyArray<{ readonly mime: string }>,
+		appended?: { valueBytes: Uint8Array; previousVersion: number }
 	): ExtendedOutputItem {
 
 		function create(
@@ -821,12 +823,20 @@ async function webviewPreloads(ctx: PreloadContext) {
 			mime: string,
 			metadata: unknown,
 			valueBytes: Uint8Array,
+			appended?: { valueBytes: Uint8Array; previousVersion: number }
 		): ExtendedOutputItem {
 			return Object.freeze<ExtendedOutputItem>({
 				id,
 				mime,
 				metadata,
 
+				appendedText(): string | undefined {
+					if (appended) {
+						return textDecoder.decode(appended.valueBytes);
+					}
+					return undefined;
+				},
+
 				data(): Uint8Array {
 					return valueBytes;
 				},
@@ -874,7 +884,7 @@ async function webviewPreloads(ctx: PreloadContext) {
 			});
 		}));
 
-		const item = create(id, mime, metadata, valueBytes);
+		const item = create(id, mime, metadata, valueBytes, appended);
 		allOutputItemCache.set(mime, Promise.resolve(item));
 		return item;
 	}
@@ -2542,7 +2552,7 @@ async function webviewPreloads(ctx: PreloadContext) {
 				const errors = preloadErrors.filter((e): e is Error => e instanceof Error);
 				showRenderError(`Error loading preloads`, this.element, errors);
 			} else {
-				const item = createOutputItem(this.outputId, content.output.mime, content.metadata, content.output.valueBytes, content.allOutputs);
+				const item = createOutputItem(this.outputId, content.output.mime, content.metadata, content.output.valueBytes, content.allOutputs, content.output.appended);
 
 				const controller = new AbortController();
 				this.renderTaskAbort = controller;