diff --git a/vscode.proposed.d.ts b/vscode.proposed.d.ts
index b687b47515..ab11cf5f55 100644
--- a/vscode.proposed.d.ts
+++ b/vscode.proposed.d.ts
@@ -599,16 +599,16 @@ declare module 'vscode' {
 		 * resolve the raw content for `uri` as the resouce is not necessarily a file on disk.
 		 */
 		// eslint-disable-next-line vscode-dts-provider-naming
-		openNotebook(uri: Uri, openContext: NotebookDocumentOpenContext): NotebookData | Promise<NotebookData>;
+		openNotebook(uri: Uri, openContext: NotebookDocumentOpenContext): NotebookData | Thenable<NotebookData>;
 		// eslint-disable-next-line vscode-dts-provider-naming
 		// eslint-disable-next-line vscode-dts-cancellation
-		resolveNotebook(document: NotebookDocument, webview: NotebookCommunication): Promise<void>;
+		resolveNotebook(document: NotebookDocument, webview: NotebookCommunication): Thenable<void>;
 		// eslint-disable-next-line vscode-dts-provider-naming
-		saveNotebook(document: NotebookDocument, cancellation: CancellationToken): Promise<void>;
+		saveNotebook(document: NotebookDocument, cancellation: CancellationToken): Thenable<void>;
 		// eslint-disable-next-line vscode-dts-provider-naming
-		saveNotebookAs(targetResource: Uri, document: NotebookDocument, cancellation: CancellationToken): Promise<void>;
+		saveNotebookAs(targetResource: Uri, document: NotebookDocument, cancellation: CancellationToken): Thenable<void>;
 		// eslint-disable-next-line vscode-dts-provider-naming
-		backupNotebook(document: NotebookDocument, context: NotebookDocumentBackupContext, cancellation: CancellationToken): Promise<NotebookDocumentBackup>;
+		backupNotebook(document: NotebookDocument, context: NotebookDocumentBackupContext, cancellation: CancellationToken): Thenable<NotebookDocumentBackup>;
 	}
 
 	export interface NotebookKernel {
@@ -707,7 +707,7 @@ declare module 'vscode' {
 		): Disposable;
 
 		export function createNotebookEditorDecorationType(options: NotebookDecorationRenderOptions): NotebookEditorDecorationType;
-		export function openNotebookDocument(uri: Uri, viewType?: string): Promise<NotebookDocument>;
+		export function openNotebookDocument(uri: Uri, viewType?: string): Thenable<NotebookDocument>;
 		export const onDidOpenNotebookDocument: Event<NotebookDocument>;
 		export const onDidCloseNotebookDocument: Event<NotebookDocument>;
 		export const onDidSaveNotebookDocument: Event<NotebookDocument>;
@@ -751,7 +751,7 @@ declare module 'vscode' {
 		export const onDidChangeActiveNotebookEditor: Event<NotebookEditor | undefined>;
 		export const onDidChangeNotebookEditorSelection: Event<NotebookEditorSelectionChangeEvent>;
 		export const onDidChangeNotebookEditorVisibleRanges: Event<NotebookEditorVisibleRangesChangeEvent>;
-		export function showNotebookDocument(document: NotebookDocument, options?: NotebookDocumentShowOptions): Promise<NotebookEditor>;
+		export function showNotebookDocument(document: NotebookDocument, options?: NotebookDocumentShowOptions): Thenable<NotebookEditor>;
 	}
 
 	//#endregion