src/vs/platform/update/electron-main/abstractUpdateService.ts/AbstractUpdateService/isLatestVersion
class AbstractUpdateService:	isLatestVersion(): Promise<boolean | undefined> {
		if (!this.url) {
			return Promise.resolve(undefined);
		}

		return this.requestService.request({ url: this.url }, CancellationToken.None).then(context => {
			// The update server replies with 204 (No Content) when no
			// update is available - that's all we want to know.
			if (context.res.statusCode === 204) {
				return true;
			} else {
				return false;
			}
		});
	}