Add option to refreshToken to force /v1 prefix

Author: davidisaaclee

src/client.ts

@@ -468,6 +468,16 @@ export interface IStoredClientOpts extends IStartClientOpts {
     canResetEntireTimeline: ResetTimelineCallback;
 }
 
+export interface IRefreshTokenOpts {
+    /**
+     * If true, forces refreshToken to use `/v1` API prefix instead of correct
+     * `/v3`. Useful for targeting Synapse before v1.72.
+     * https://github.com/matrix-org/synapse/pull/14364
+     * @defaultValue false
+     */
+    forcePrefixV1?: boolean;
+}
+
 export enum RoomVersionStability {
     Stable = "stable",
     Unstable = "unstable",
@@ -7517,14 +7527,14 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
      * @returns Promise which resolves to the new token.
      * @returns Rejects with an error response.
      */
-    public refreshToken(refreshToken: string): Promise<IRefreshTokenResponse> {
+    public refreshToken(refreshToken: string, options: IRefreshTokenOpts = {}): Promise<IRefreshTokenResponse> {
         return this.http.authedRequest(
             Method.Post,
             "/refresh",
             undefined,
             { refresh_token: refreshToken },
             {
-                prefix: ClientPrefix.V3,
+                prefix: options.forcePrefixV1 ? ClientPrefix.V1 : ClientPrefix.V3,
                 inhibitLogoutEmit: true, // we don't want to cause logout loops
             },
         );