message: Back compat: DeltaManager.lastSequenceNumber
diff: @@ -402,6 +402,13 @@ export class ContainerRuntime extends EventEmitter implements IContainerRuntime,
  runtimeOptions?: IContainerRuntimeOptions,
  containerScope: IComponent = context.scope,
  ): Promise<ContainerRuntime> {
  + // Back-compat: <= 0.18 loader
  + if (context.deltaManager.lastSequenceNumber === undefined) {
  + Object.defineProperty(context.deltaManager, "lastSequenceNumber", {
  + get: () => (context.deltaManager as any).referenceSequenceNumber,
  + });
  + }
  +
  const componentRegistry = new ContainerRuntimeComponentRegistry(registryEntries);
  const chunkId = context.baseSnapshot?.blobs[".chunks"];
  