diff --git a/keyserver/flow-typed/npm/express_v4.17.x.js b/keyserver/flow-typed/npm/express_v4.17.x.js
index d932b6597..de23f127f 100644
--- a/keyserver/flow-typed/npm/express_v4.17.x.js
+++ b/keyserver/flow-typed/npm/express_v4.17.x.js
@@ -1,369 +1,372 @@
 // flow-typed signature: e325fc5832ca944b2b2735ebbebbab61
 // flow-typed version: 4cce735749/express_v4.17.x/flow_>=v0.104.x
 
 declare type express$RouterOptions = {
   caseSensitive?: boolean,
   mergeParams?: boolean,
   strict?: boolean,
   ...
 };
 
 declare class express$RequestResponseBase {
   app: express$Application<any, any>;
   get(field: string): string | void;
 }
 
 declare type express$RangeParserOptions = {|
   +combine?: boolean,
 |};
 
 declare type express$RangeParserRange = {|
   +start: number,
   +end: number,
 |};
 
 declare type express$RequestParams = { [param: string]: string, ... };
 
 /*
   NOTE: Use caution when extending `express$Request` or `express$Response`. When
   a request first hits the server, its `req` and `res` will not have any
   additional properties, even if you explicitly type them with your custom
   subclass. Subsequent middleware may assign these properties, but you must be
   cognizant of this ordering. One way to handle this is marking all properties
   as optional to force refinement every time a property is accessed. Therefore,
   we advise that you always mark properties as _optional_ in `express$Request`
   and `express$Response` subclasses.
 
   You may decide not to do this, in which case the typings will be unsound and
   the behavior will be similar to how arrays work in Flow. See here for more
   information: https://flow.org/en/docs/types/arrays/#toc-array-access-is-unsafe
 
   See #3578 and #3337 for additional discussion. If you have ideas on how to
   improve these typings, please share them in #3578 or open a new issue.
 
   **BAD**
   declare class test_express$CustomRequest extends express$Request {
     foo: string;
   }
 
   **GOOD**
   declare class test_express$CustomRequest extends express$Request {
     foo: string | void;
   }
 */
 declare class express$Request extends http$IncomingMessage mixins express$RequestResponseBase {
   baseUrl: string;
   body: mixed;
   cookies: { [cookie: string]: string, ... };
   connection: net$Socket;
   fresh: boolean;
   hostname: string;
   ip: string;
   ips: Array<string>;
   method: string;
   originalUrl: string;
   params: express$RequestParams;
   path: string;
   protocol: "https" | "http";
   query: { [name: string]: string | Array<string>, ... };
   res?: express$Response;
   route: string;
   secure: boolean;
   signedCookies: { [signedCookie: string]: string, ... };
   stale: boolean;
   subdomains: Array<string>;
   xhr: boolean;
   accepts(types: string): string | false;
   accepts(types: Array<string>): string | false;
   acceptsCharsets(...charsets: Array<string>): string | false;
   acceptsEncodings(...encoding: Array<string>): string | false;
   acceptsLanguages(...lang: Array<string>): string | false;
   header(field: string): string | void;
   is(type: string): string | false;
   param(name: string, defaultValue?: string): string | void;
   range(size: number, options?: express$RangeParserOptions): Array<express$RangeParserRange> | number | void;
 }
 
 declare type express$CookieOptions = {
   domain?: string,
   encode?: (value: string) => string,
   expires?: Date,
   httpOnly?: boolean,
   maxAge?: number,
   path?: string,
   secure?: boolean,
   signed?: boolean,
   sameSite?: boolean | string,
   ...
 };
 
 declare type express$Path = string | RegExp;
 
 declare type express$RenderCallback = (
   err: Error | null,
   html?: string
 ) => mixed;
 
 declare type express$SendFileOptions = {
   maxAge?: number,
   root?: string,
   lastModified?: boolean,
   headers?: { [name: string]: string, ... },
   dotfiles?: "allow" | "deny" | "ignore",
   ...
 };
 
 declare class express$Response extends http$ServerResponse mixins express$RequestResponseBase {
   headersSent: boolean;
   locals: { [name: string]: mixed, ... };
   append(field: string, value?: string): this;
   attachment(filename?: string): this;
   cookie(name: string, value: string, options?: express$CookieOptions): this;
   clearCookie(name: string, options?: express$CookieOptions): this;
   download(
     path: string,
     filename?: string,
     callback?: (err?: ?Error) => void
   ): this;
   format(typesObject: { [type: string]: Function, ... }): this;
   json(body?: mixed): this;
   jsonp(body?: mixed): this;
   links(links: { [name: string]: string, ... }): this;
   location(path: string): this;
   redirect(url: string, ...args: Array<void>): this;
   redirect(status: number, url: string, ...args: Array<void>): this;
   render(
     view: string,
     locals?: { [name: string]: mixed, ... },
     callback?: express$RenderCallback
   ): this;
   render(
     view: string,
     callback?: express$RenderCallback
   ): this;
   send(body?: mixed): this;
   sendFile(
     path: string,
     options?: express$SendFileOptions,
     callback?: (err?: ?Error) => mixed
   ): this;
   sendStatus(statusCode: number): this;
   header(field: string, value?: string): this;
   header(headers: { [name: string]: string, ... }): this;
   set(field: string, value?: string | string[]): this;
   set(headers: { [name: string]: string, ... }): this;
   status(statusCode: number): this;
   type(type: string): this;
   vary(field: string): this;
   req: express$Request;
 }
 
 declare type express$NextFunction = (err?: ?Error | "route") => mixed;
 declare type express$Middleware<
   Req: express$Request = express$Request,
   Res: express$Response = express$Response,
 > =
   ((req: Req, res: Res, next: express$NextFunction) => mixed) |
   ((error: Error, req: Req, res: Res, next: express$NextFunction) => mixed);
 
 declare interface express$RouteMethodType<
   T,
   Req: express$Request = express$Request,
   Res: express$Response = express$Response,
 > {
   (middleware: express$Middleware<Req, Res>): T;
   (...middleware: Array<express$Middleware<Req, Res>>): T;
   (
     path: express$Path | $ReadOnlyArray<express$Path>,
     ...middleware: Array<express$Middleware<Req, Res>>
   ): T;
 }
 
 declare class express$Route<
   Req: express$Request = express$Request,
   Res: express$Response = express$Response,
 > {
   all: express$RouteMethodType<this, Req, Res>;
   get: express$RouteMethodType<this, Req, Res>;
   post: express$RouteMethodType<this, Req, Res>;
   put: express$RouteMethodType<this, Req, Res>;
   head: express$RouteMethodType<this, Req, Res>;
   delete: express$RouteMethodType<this, Req, Res>;
   options: express$RouteMethodType<this, Req, Res>;
   trace: express$RouteMethodType<this, Req, Res>;
   copy: express$RouteMethodType<this, Req, Res>;
   lock: express$RouteMethodType<this, Req, Res>;
   mkcol: express$RouteMethodType<this, Req, Res>;
   move: express$RouteMethodType<this, Req, Res>;
   purge: express$RouteMethodType<this, Req, Res>;
   propfind: express$RouteMethodType<this, Req, Res>;
   proppatch: express$RouteMethodType<this, Req, Res>;
   unlock: express$RouteMethodType<this, Req, Res>;
   report: express$RouteMethodType<this, Req, Res>;
   mkactivity: express$RouteMethodType<this, Req, Res>;
   checkout: express$RouteMethodType<this, Req, Res>;
   merge: express$RouteMethodType<this, Req, Res>;
 
   // @TODO Missing 'm-search' but get flow illegal name error.
 
   notify: express$RouteMethodType<this, Req, Res>;
   subscribe: express$RouteMethodType<this, Req, Res>;
   unsubscribe: express$RouteMethodType<this, Req, Res>;
   patch: express$RouteMethodType<this, Req, Res>;
   search: express$RouteMethodType<this, Req, Res>;
   connect: express$RouteMethodType<this, Req, Res>;
 }
 
 declare type express$RouterUseable<Req: express$Request, Res: express$Response> =
   | express$Middleware<Req, Res>
   | express$Router<Req, Res>
   | $ReadOnlyArray<express$Middleware<Req, Res> | express$Router<Req, Res>>;
 
 declare class express$Router<
   Req: express$Request = express$Request,
   Res: express$Response = express$Response,
 > extends express$Route<Req, Res> {
   constructor(options?: express$RouterOptions): void;
   route(path: string): express$Route<Req, Res>;
   static <Req2: express$Request, Res2: express$Response>(
     options?: express$RouterOptions,
   ): express$Router<Req2, Res2>;
   use(express$RouterUseable<Req, Res>, ...express$RouterUseable<Req, Res>[]): this;
   use(express$Path, express$RouterUseable<Req, Res>, ...express$RouterUseable<Req, Res>[]): this;
   handle(
     req: http$IncomingMessage<>,
     res: http$ServerResponse,
     next: express$NextFunction
   ): void;
   param(
     param: string,
     callback: (
       req: Req,
       res: Res,
       next: express$NextFunction,
       value: string,
       paramName: string,
     ) => mixed
   ): void;
   (
     req: http$IncomingMessage<>,
     res: http$ServerResponse,
     next?: ?express$NextFunction
   ): void;
 }
 
 /*
 With flow-bin ^0.59, express app.listen() is deemed to return any and fails flow type coverage.
 Which is ironic because https://github.com/facebook/flow/blob/master/Changelog.md#misc-2 (release notes for 0.59)
 says "Improves typings for Node.js HTTP server listen() function."  See that?  IMPROVES!
 To work around this issue, we changed Server to ?Server here, so that our invocations of express.listen() will
 not be deemed to lack type coverage.
 */
 
 declare class express$Application<
   Req: express$Request = express$Request,
   Res: express$Response = express$Response,
 > extends express$Router<Req, Res> mixins events$EventEmitter {
   constructor(): void;
   locals: { [name: string]: mixed, ... };
   mountpath: string;
   listen(
     port: number,
     hostname?: string,
     backlog?: number,
     callback?: (err?: ?Error) => mixed
   ): ?http$Server;
   listen(
     port: number,
     hostname?: string,
     callback?: (err?: ?Error) => mixed
   ): ?http$Server;
   listen(port: number, callback?: (err?: ?Error) => mixed): ?http$Server;
   listen(path: string, callback?: (err?: ?Error) => mixed): ?http$Server;
   listen(handle: Object, callback?: (err?: ?Error) => mixed): ?http$Server;
   disable(name: string): void;
   disabled(name: string): boolean;
   enable(name: string): this;
   enabled(name: string): boolean;
   engine(name: string, callback: Function): void;
   /**
    * Mixed will not be taken as a value option. Issue around using the GET http method name and the get for settings.
    */
   //   get(name: string): mixed;
   set(name: string, value: mixed): mixed;
   render(
     name: string,
     optionsOrFunction: { [name: string]: mixed, ... },
     callback: express$RenderCallback
   ): void;
   handle(
     req: http$IncomingMessage<>,
     res: http$ServerResponse,
     next?: ?express$NextFunction
   ): void;
   // callable signature is not inherited
   (
     req: http$IncomingMessage<>,
     res: http$ServerResponse,
     next?: ?express$NextFunction
   ): void;
 }
 
 declare type JsonOptions = {
   inflate?: boolean,
   limit?: string | number,
   reviver?: (key: string, value: mixed) => mixed,
   strict?: boolean,
   type?: string | Array<string> | ((req: express$Request) => boolean),
   verify?: (
     req: express$Request,
     res: express$Response,
     buf: Buffer,
     encoding: string
   ) => mixed,
   ...
 };
 
 declare type express$UrlEncodedOptions = {
   extended?: boolean,
   inflate?: boolean,
   limit?: string | number,
   parameterLimit?: number,
   type?: string | Array<string> | ((req: express$Request) => boolean),
   verify?: (
     req: express$Request,
     res: express$Response,
     buf: Buffer,
     encoding: string
   ) => mixed,
   ...
 }
 
 declare module "express" {
   declare export type RouterOptions = express$RouterOptions;
   declare export type CookieOptions = express$CookieOptions;
   declare export type Middleware<
     Req: express$Request = express$Request,
     Res: express$Response = express$Response,
   > = express$Middleware<Req, Res>;
   declare export type NextFunction = express$NextFunction;
   declare export type RequestParams = express$RequestParams;
   declare export type $Response = express$Response;
   declare export type $Request = express$Request;
   declare export type $Application<
     Req: express$Request = express$Request,
     Res: express$Response = express$Response,
   > = express$Application<Req, Res>;
 
   declare module.exports: {
     // If you try to call like a function, it will use this signature
-    <Req: express$Request, Res: express$Response>(): express$Application<Req, Res>,
+    <
+      Req: express$Request = express$Request,
+      Res: express$Response = express$Response,
+    >(): express$Application<Req, Res>,
     json: (opts: ?JsonOptions) => express$Middleware<>,
     // `static` property on the function
     static: <Req: express$Request, Res: express$Response>(root: string, options?: Object) => express$Middleware<Req, Res>,
     // `Router` property on the function
     Router: typeof express$Router,
     urlencoded: (opts: ?express$UrlEncodedOptions) => express$Middleware<>,
     ...
   };
 }
diff --git a/services/electron-update-server/flow-typed/npm/express_v4.17.x.js b/services/electron-update-server/flow-typed/npm/express_v4.17.x.js
index d932b6597..de23f127f 100644
--- a/services/electron-update-server/flow-typed/npm/express_v4.17.x.js
+++ b/services/electron-update-server/flow-typed/npm/express_v4.17.x.js
@@ -1,369 +1,372 @@
 // flow-typed signature: e325fc5832ca944b2b2735ebbebbab61
 // flow-typed version: 4cce735749/express_v4.17.x/flow_>=v0.104.x
 
 declare type express$RouterOptions = {
   caseSensitive?: boolean,
   mergeParams?: boolean,
   strict?: boolean,
   ...
 };
 
 declare class express$RequestResponseBase {
   app: express$Application<any, any>;
   get(field: string): string | void;
 }
 
 declare type express$RangeParserOptions = {|
   +combine?: boolean,
 |};
 
 declare type express$RangeParserRange = {|
   +start: number,
   +end: number,
 |};
 
 declare type express$RequestParams = { [param: string]: string, ... };
 
 /*
   NOTE: Use caution when extending `express$Request` or `express$Response`. When
   a request first hits the server, its `req` and `res` will not have any
   additional properties, even if you explicitly type them with your custom
   subclass. Subsequent middleware may assign these properties, but you must be
   cognizant of this ordering. One way to handle this is marking all properties
   as optional to force refinement every time a property is accessed. Therefore,
   we advise that you always mark properties as _optional_ in `express$Request`
   and `express$Response` subclasses.
 
   You may decide not to do this, in which case the typings will be unsound and
   the behavior will be similar to how arrays work in Flow. See here for more
   information: https://flow.org/en/docs/types/arrays/#toc-array-access-is-unsafe
 
   See #3578 and #3337 for additional discussion. If you have ideas on how to
   improve these typings, please share them in #3578 or open a new issue.
 
   **BAD**
   declare class test_express$CustomRequest extends express$Request {
     foo: string;
   }
 
   **GOOD**
   declare class test_express$CustomRequest extends express$Request {
     foo: string | void;
   }
 */
 declare class express$Request extends http$IncomingMessage mixins express$RequestResponseBase {
   baseUrl: string;
   body: mixed;
   cookies: { [cookie: string]: string, ... };
   connection: net$Socket;
   fresh: boolean;
   hostname: string;
   ip: string;
   ips: Array<string>;
   method: string;
   originalUrl: string;
   params: express$RequestParams;
   path: string;
   protocol: "https" | "http";
   query: { [name: string]: string | Array<string>, ... };
   res?: express$Response;
   route: string;
   secure: boolean;
   signedCookies: { [signedCookie: string]: string, ... };
   stale: boolean;
   subdomains: Array<string>;
   xhr: boolean;
   accepts(types: string): string | false;
   accepts(types: Array<string>): string | false;
   acceptsCharsets(...charsets: Array<string>): string | false;
   acceptsEncodings(...encoding: Array<string>): string | false;
   acceptsLanguages(...lang: Array<string>): string | false;
   header(field: string): string | void;
   is(type: string): string | false;
   param(name: string, defaultValue?: string): string | void;
   range(size: number, options?: express$RangeParserOptions): Array<express$RangeParserRange> | number | void;
 }
 
 declare type express$CookieOptions = {
   domain?: string,
   encode?: (value: string) => string,
   expires?: Date,
   httpOnly?: boolean,
   maxAge?: number,
   path?: string,
   secure?: boolean,
   signed?: boolean,
   sameSite?: boolean | string,
   ...
 };
 
 declare type express$Path = string | RegExp;
 
 declare type express$RenderCallback = (
   err: Error | null,
   html?: string
 ) => mixed;
 
 declare type express$SendFileOptions = {
   maxAge?: number,
   root?: string,
   lastModified?: boolean,
   headers?: { [name: string]: string, ... },
   dotfiles?: "allow" | "deny" | "ignore",
   ...
 };
 
 declare class express$Response extends http$ServerResponse mixins express$RequestResponseBase {
   headersSent: boolean;
   locals: { [name: string]: mixed, ... };
   append(field: string, value?: string): this;
   attachment(filename?: string): this;
   cookie(name: string, value: string, options?: express$CookieOptions): this;
   clearCookie(name: string, options?: express$CookieOptions): this;
   download(
     path: string,
     filename?: string,
     callback?: (err?: ?Error) => void
   ): this;
   format(typesObject: { [type: string]: Function, ... }): this;
   json(body?: mixed): this;
   jsonp(body?: mixed): this;
   links(links: { [name: string]: string, ... }): this;
   location(path: string): this;
   redirect(url: string, ...args: Array<void>): this;
   redirect(status: number, url: string, ...args: Array<void>): this;
   render(
     view: string,
     locals?: { [name: string]: mixed, ... },
     callback?: express$RenderCallback
   ): this;
   render(
     view: string,
     callback?: express$RenderCallback
   ): this;
   send(body?: mixed): this;
   sendFile(
     path: string,
     options?: express$SendFileOptions,
     callback?: (err?: ?Error) => mixed
   ): this;
   sendStatus(statusCode: number): this;
   header(field: string, value?: string): this;
   header(headers: { [name: string]: string, ... }): this;
   set(field: string, value?: string | string[]): this;
   set(headers: { [name: string]: string, ... }): this;
   status(statusCode: number): this;
   type(type: string): this;
   vary(field: string): this;
   req: express$Request;
 }
 
 declare type express$NextFunction = (err?: ?Error | "route") => mixed;
 declare type express$Middleware<
   Req: express$Request = express$Request,
   Res: express$Response = express$Response,
 > =
   ((req: Req, res: Res, next: express$NextFunction) => mixed) |
   ((error: Error, req: Req, res: Res, next: express$NextFunction) => mixed);
 
 declare interface express$RouteMethodType<
   T,
   Req: express$Request = express$Request,
   Res: express$Response = express$Response,
 > {
   (middleware: express$Middleware<Req, Res>): T;
   (...middleware: Array<express$Middleware<Req, Res>>): T;
   (
     path: express$Path | $ReadOnlyArray<express$Path>,
     ...middleware: Array<express$Middleware<Req, Res>>
   ): T;
 }
 
 declare class express$Route<
   Req: express$Request = express$Request,
   Res: express$Response = express$Response,
 > {
   all: express$RouteMethodType<this, Req, Res>;
   get: express$RouteMethodType<this, Req, Res>;
   post: express$RouteMethodType<this, Req, Res>;
   put: express$RouteMethodType<this, Req, Res>;
   head: express$RouteMethodType<this, Req, Res>;
   delete: express$RouteMethodType<this, Req, Res>;
   options: express$RouteMethodType<this, Req, Res>;
   trace: express$RouteMethodType<this, Req, Res>;
   copy: express$RouteMethodType<this, Req, Res>;
   lock: express$RouteMethodType<this, Req, Res>;
   mkcol: express$RouteMethodType<this, Req, Res>;
   move: express$RouteMethodType<this, Req, Res>;
   purge: express$RouteMethodType<this, Req, Res>;
   propfind: express$RouteMethodType<this, Req, Res>;
   proppatch: express$RouteMethodType<this, Req, Res>;
   unlock: express$RouteMethodType<this, Req, Res>;
   report: express$RouteMethodType<this, Req, Res>;
   mkactivity: express$RouteMethodType<this, Req, Res>;
   checkout: express$RouteMethodType<this, Req, Res>;
   merge: express$RouteMethodType<this, Req, Res>;
 
   // @TODO Missing 'm-search' but get flow illegal name error.
 
   notify: express$RouteMethodType<this, Req, Res>;
   subscribe: express$RouteMethodType<this, Req, Res>;
   unsubscribe: express$RouteMethodType<this, Req, Res>;
   patch: express$RouteMethodType<this, Req, Res>;
   search: express$RouteMethodType<this, Req, Res>;
   connect: express$RouteMethodType<this, Req, Res>;
 }
 
 declare type express$RouterUseable<Req: express$Request, Res: express$Response> =
   | express$Middleware<Req, Res>
   | express$Router<Req, Res>
   | $ReadOnlyArray<express$Middleware<Req, Res> | express$Router<Req, Res>>;
 
 declare class express$Router<
   Req: express$Request = express$Request,
   Res: express$Response = express$Response,
 > extends express$Route<Req, Res> {
   constructor(options?: express$RouterOptions): void;
   route(path: string): express$Route<Req, Res>;
   static <Req2: express$Request, Res2: express$Response>(
     options?: express$RouterOptions,
   ): express$Router<Req2, Res2>;
   use(express$RouterUseable<Req, Res>, ...express$RouterUseable<Req, Res>[]): this;
   use(express$Path, express$RouterUseable<Req, Res>, ...express$RouterUseable<Req, Res>[]): this;
   handle(
     req: http$IncomingMessage<>,
     res: http$ServerResponse,
     next: express$NextFunction
   ): void;
   param(
     param: string,
     callback: (
       req: Req,
       res: Res,
       next: express$NextFunction,
       value: string,
       paramName: string,
     ) => mixed
   ): void;
   (
     req: http$IncomingMessage<>,
     res: http$ServerResponse,
     next?: ?express$NextFunction
   ): void;
 }
 
 /*
 With flow-bin ^0.59, express app.listen() is deemed to return any and fails flow type coverage.
 Which is ironic because https://github.com/facebook/flow/blob/master/Changelog.md#misc-2 (release notes for 0.59)
 says "Improves typings for Node.js HTTP server listen() function."  See that?  IMPROVES!
 To work around this issue, we changed Server to ?Server here, so that our invocations of express.listen() will
 not be deemed to lack type coverage.
 */
 
 declare class express$Application<
   Req: express$Request = express$Request,
   Res: express$Response = express$Response,
 > extends express$Router<Req, Res> mixins events$EventEmitter {
   constructor(): void;
   locals: { [name: string]: mixed, ... };
   mountpath: string;
   listen(
     port: number,
     hostname?: string,
     backlog?: number,
     callback?: (err?: ?Error) => mixed
   ): ?http$Server;
   listen(
     port: number,
     hostname?: string,
     callback?: (err?: ?Error) => mixed
   ): ?http$Server;
   listen(port: number, callback?: (err?: ?Error) => mixed): ?http$Server;
   listen(path: string, callback?: (err?: ?Error) => mixed): ?http$Server;
   listen(handle: Object, callback?: (err?: ?Error) => mixed): ?http$Server;
   disable(name: string): void;
   disabled(name: string): boolean;
   enable(name: string): this;
   enabled(name: string): boolean;
   engine(name: string, callback: Function): void;
   /**
    * Mixed will not be taken as a value option. Issue around using the GET http method name and the get for settings.
    */
   //   get(name: string): mixed;
   set(name: string, value: mixed): mixed;
   render(
     name: string,
     optionsOrFunction: { [name: string]: mixed, ... },
     callback: express$RenderCallback
   ): void;
   handle(
     req: http$IncomingMessage<>,
     res: http$ServerResponse,
     next?: ?express$NextFunction
   ): void;
   // callable signature is not inherited
   (
     req: http$IncomingMessage<>,
     res: http$ServerResponse,
     next?: ?express$NextFunction
   ): void;
 }
 
 declare type JsonOptions = {
   inflate?: boolean,
   limit?: string | number,
   reviver?: (key: string, value: mixed) => mixed,
   strict?: boolean,
   type?: string | Array<string> | ((req: express$Request) => boolean),
   verify?: (
     req: express$Request,
     res: express$Response,
     buf: Buffer,
     encoding: string
   ) => mixed,
   ...
 };
 
 declare type express$UrlEncodedOptions = {
   extended?: boolean,
   inflate?: boolean,
   limit?: string | number,
   parameterLimit?: number,
   type?: string | Array<string> | ((req: express$Request) => boolean),
   verify?: (
     req: express$Request,
     res: express$Response,
     buf: Buffer,
     encoding: string
   ) => mixed,
   ...
 }
 
 declare module "express" {
   declare export type RouterOptions = express$RouterOptions;
   declare export type CookieOptions = express$CookieOptions;
   declare export type Middleware<
     Req: express$Request = express$Request,
     Res: express$Response = express$Response,
   > = express$Middleware<Req, Res>;
   declare export type NextFunction = express$NextFunction;
   declare export type RequestParams = express$RequestParams;
   declare export type $Response = express$Response;
   declare export type $Request = express$Request;
   declare export type $Application<
     Req: express$Request = express$Request,
     Res: express$Response = express$Response,
   > = express$Application<Req, Res>;
 
   declare module.exports: {
     // If you try to call like a function, it will use this signature
-    <Req: express$Request, Res: express$Response>(): express$Application<Req, Res>,
+    <
+      Req: express$Request = express$Request,
+      Res: express$Response = express$Response,
+    >(): express$Application<Req, Res>,
     json: (opts: ?JsonOptions) => express$Middleware<>,
     // `static` property on the function
     static: <Req: express$Request, Res: express$Response>(root: string, options?: Object) => express$Middleware<Req, Res>,
     // `Router` property on the function
     Router: typeof express$Router,
     urlencoded: (opts: ?express$UrlEncodedOptions) => express$Middleware<>,
     ...
   };
 }
diff --git a/services/electron-update-server/flow-typed/npm/hazel-server_vx.x.x.js b/services/electron-update-server/flow-typed/npm/hazel-server_vx.x.x.js
index 99b7bdfa4..19c017f28 100644
--- a/services/electron-update-server/flow-typed/npm/hazel-server_vx.x.x.js
+++ b/services/electron-update-server/flow-typed/npm/hazel-server_vx.x.x.js
@@ -1,15 +1,17 @@
 // @flow
 
 // flow-typed signature: e7cb9cb805c20a715f16a8385248ee0b
 // flow-typed version: <<STUB>>/hazel-server_v5.1.1/flow_v0.198.1
 
 declare module 'hazel-server' {
+  import type { $Response, $Request } from 'express';
+
   declare export default function hazel(options: {
     interval?: number,
     repository?: string,
     account?: string,
     pre?: boolean,
     token?: string,
     url?: string,
-  }): (Request, Response) => void;
+  }): ($Request, $Response) => void;
 }
diff --git a/services/electron-update-server/index.js b/services/electron-update-server/index.js
index 4f17f8949..bdd8edf88 100644
--- a/services/electron-update-server/index.js
+++ b/services/electron-update-server/index.js
@@ -1,18 +1,19 @@
 // @flow
 
 import express from 'express';
+import type { $Request, $Response } from 'express';
 import hazel from 'hazel-server';
 
 const hazelServer = hazel({
   // Cache refresh interval (in minutes)
   interval: 15,
   repository: process.env.HAZEL_REPOSITORY ?? 'comm',
   account: process.env.HAZEL_ACCOUNT ?? 'CommE2e',
 });
 
 const app = express();
-app.all('*', (req, res) => {
+app.all('*', (req: $Request, res: $Response) => {
   hazelServer(req, res);
 });
 
 app.listen(parseInt(process.env.HAZEL_PORT, 10) || 80);