diff --git a/keyserver/src/responders/website-responders.js b/keyserver/src/responders/website-responders.js
index 9918ade7c..cdb8fee38 100644
--- a/keyserver/src/responders/website-responders.js
+++ b/keyserver/src/responders/website-responders.js
@@ -1,407 +1,407 @@
 // @flow
 
 import html from 'common-tags/lib/html/index.js';
 import { detect as detectBrowser } from 'detect-browser';
 import type { $Response, $Request } from 'express';
 import fs from 'fs';
 import * as React from 'react';
 // eslint-disable-next-line import/extensions
 import ReactDOMServer from 'react-dom/server';
 import { promisify } from 'util';
 
 import stores from 'lib/facts/stores.js';
 import { inviteSecretRegex } from 'lib/shared/invite-links-constants.js';
 import getTitle from 'web/title/get-title.js';
 
 import { waitForStream } from '../utils/json-stream.js';
 import {
   getAndAssertKeyserverURLFacts,
   getAppURLFactsFromRequestURL,
   getWebAppURLFacts,
 } from '../utils/urls.js';
 
 // eslint-disable-next-line react/no-deprecated
 const { renderToNodeStream } = ReactDOMServer;
 
 const access = promisify(fs.access);
 const readFile = promisify(fs.readFile);
 
 const googleFontsURL =
   'https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:wght@400;500;600&family=Inter:wght@400;500;600&display=swap';
 const localFontsURL = 'fonts/local-fonts.css';
 async function getFontsURL() {
   try {
     await access(localFontsURL);
     return localFontsURL;
   } catch {
     return googleFontsURL;
   }
 }
 
 type AssetInfo = {
   +jsURL: string,
   +fontsURL: string,
   +cssInclude: string,
   +olmFilename: string,
   +commQueryExecutorFilename: string,
   +backupClientFilename: string,
   +webworkersOpaqueFilename: string,
 };
 let assetInfo: ?AssetInfo = null;
 async function getAssetInfo() {
   if (assetInfo) {
     return assetInfo;
   }
   if (process.env.NODE_ENV === 'development') {
     const fontsURL = await getFontsURL();
     assetInfo = {
       jsURL: 'http://localhost:8080/dev.build.js',
       fontsURL,
       cssInclude: '',
       olmFilename: '',
       commQueryExecutorFilename: '',
       backupClientFilename: '',
       webworkersOpaqueFilename: '',
     };
     return assetInfo;
   }
   try {
     const manifestString = await readFile('../web/dist/manifest.json', 'utf8');
     const manifest = JSON.parse(manifestString);
     const webworkersManifestString = await readFile(
       '../web/dist/webworkers/manifest.json',
       'utf8',
     );
     const webworkersManifest = JSON.parse(webworkersManifestString);
     assetInfo = {
       jsURL: `compiled/${manifest['browser.js']}`,
       fontsURL: googleFontsURL,
       cssInclude: html`
         <link
           rel="stylesheet"
           type="text/css"
           href="compiled/${manifest['browser.css']}"
         />
       `,
       olmFilename: manifest['olm.wasm'],
       commQueryExecutorFilename: webworkersManifest['comm_query_executor.wasm'],
       backupClientFilename: webworkersManifest['backup-client-wasm_bg.wasm'],
       webworkersOpaqueFilename: webworkersManifest['comm_opaque2_wasm_bg.wasm'],
     };
     return assetInfo;
   } catch (e) {
     console.warn(e);
     throw new Error(
       'Could not load manifest.json for web build. ' +
         'Did you forget to run `yarn dev` in the web folder?',
     );
   }
 }
 
 let webpackCompiledRootComponent: ?React.ComponentType<{}> = null;
 async function getWebpackCompiledRootComponentForSSR() {
   if (webpackCompiledRootComponent) {
     return webpackCompiledRootComponent;
   }
   try {
     // $FlowFixMe web/dist doesn't always exist
     const webpackBuild = await import('web/dist/app.build.cjs');
     webpackCompiledRootComponent = webpackBuild.app.default;
     return webpackCompiledRootComponent;
   } catch (e) {
     console.warn(e);
     throw new Error(
       'Could not load app.build.cjs. ' +
         'Did you forget to run `yarn dev` in the web folder?',
     );
   }
 }
 
 function stripLastSlash(input: string): string {
   return input.replace(/\/$/, '');
 }
 
 async function websiteResponder(req: $Request, res: $Response): Promise<void> {
   const { basePath } = getAppURLFactsFromRequestURL(req.originalUrl);
   const baseURL = stripLastSlash(basePath);
 
   const keyserverURLFacts = getAndAssertKeyserverURLFacts();
   const keyserverURL = `${keyserverURLFacts.baseDomain}${stripLastSlash(
     keyserverURLFacts.basePath,
   )}`;
 
   const loadingPromise = getWebpackCompiledRootComponentForSSR();
 
   const assetInfoPromise = getAssetInfo();
   const {
     jsURL,
     fontsURL,
     cssInclude,
     olmFilename,
     commQueryExecutorFilename,
     backupClientFilename,
     webworkersOpaqueFilename,
   } = await assetInfoPromise;
 
   // prettier-ignore
   res.write(html`
     <!DOCTYPE html>
     <html lang="en">
       <head>
         <meta charset="utf-8" />
         <title>${getTitle(0)}</title>
         <base href="${basePath}" />
         <link rel="stylesheet" type="text/css" href="${fontsURL}" />
         ${cssInclude}
         <link
           rel="apple-touch-icon"
           sizes="180x180"
           href="apple-touch-icon.png"
         />
         <link
           rel="icon"
           type="image/png"
           sizes="32x32"
           href="favicon-32x32.png"
         />
         <link
           rel="icon"
           type="image/png"
           sizes="16x16"
           href="favicon-16x16.png"
         />
         <link rel="manifest" href="site.webmanifest" />
         <meta name="apple-mobile-web-app-title" content="Comm" />
         <meta name="application-name" content="Comm" />
         <meta name="msapplication-TileColor" content="#b91d47" />
         <meta name="theme-color" content="#b91d47" />
       </head>
       <body>
         <div id="react-root">
   `);
 
   const Loading = await loadingPromise;
   const reactStream = renderToNodeStream(<Loading />);
   reactStream.pipe(res, { end: false });
 
   await waitForStream(reactStream);
   res.end(html`
     </div>
     <script>
           var keyserverURL = "${keyserverURL}";
           var baseURL = "${baseURL}";
           var olmFilename = "${olmFilename}";
           var commQueryExecutorFilename = "${commQueryExecutorFilename}";
           var backupClientFilename = "${backupClientFilename}";
           var webworkersOpaqueFilename = "${webworkersOpaqueFilename}"
         </script>
         <script src="${jsURL}"></script>
       </body>
     </html>
   `);
 }
 
 // On native, if this responder is called, it means that the app isn't
 // installed.
 async function inviteResponder(req: $Request, res: $Response): Promise<void> {
   const { secret } = req.params;
   const userAgent = req.get('User-Agent');
   const detectionResult = detectBrowser(userAgent);
-  if (detectionResult.os === 'Android OS') {
+  if (detectionResult?.os === 'Android OS') {
     const isSecretValid = inviteSecretRegex.test(secret);
     const referrer = isSecretValid
       ? `&referrer=${encodeURIComponent(`utm_source=invite/${secret}`)}`
       : '';
     const redirectUrl = `${stores.googlePlayUrl}${referrer}`;
     res.writeHead(301, {
       Location: redirectUrl,
     });
     res.end();
     return;
-  } else if (detectionResult.os !== 'iOS') {
+  } else if (detectionResult?.os !== 'iOS') {
     const urlFacts = getWebAppURLFacts();
     const baseDomain = urlFacts?.baseDomain ?? '';
     const basePath = urlFacts?.basePath ?? '/';
     const redirectUrl = `${baseDomain}${basePath}handle/invite/${secret}`;
     res.writeHead(301, {
       Location: redirectUrl,
     });
     res.end();
     return;
   }
   const fontsURL = await getFontsURL();
   res.end(html`
     <!doctype html>
     <html lang="en">
       <head>
         <meta charset="utf-8" />
         <title>Comm</title>
         <link rel="stylesheet" type="text/css" href="/${fontsURL}" />
         <style>
           * {
             -webkit-font-smoothing: antialiased;
             -moz-osx-font-smoothing: grayscale;
             box-sizing: border-box;
             padding: 0;
             margin: 0;
           }
 
           html {
             height: 100%;
             font-size: 112.5%;
           }
 
           body {
             font-family:
               'Inter',
               -apple-system,
               'Segoe UI',
               'Roboto',
               'Oxygen',
               'Ubuntu',
               'Cantarell',
               'Fira Sans',
               'Droid Sans',
               'Helvetica Neue',
               ui-sans-serif;
             background: #0a0a0a url('/images/invite_link_background.png')
               no-repeat;
             background-size: cover;
             color: #ffffff;
             display: flex;
             flex-direction: column;
             justify-content: space-around;
             align-items: center;
             height: 100%;
             padding: 1.6rem;
             font-size: 1.8rem;
             line-height: 2.4rem;
             font-weight: 500;
           }
 
           section {
             display: flex;
             flex-direction: column;
             align-items: center;
             justify-content: space-between;
             width: 100%;
           }
 
           .card {
             width: 100%;
             padding: 3.2rem 1.6rem;
             gap: 4rem;
             background-color: #1f1f1f;
             border-radius: 1.6rem;
           }
 
           .buttons {
             gap: 1.2rem;
           }
 
           h1 {
             font-size: 3.6rem;
             line-height: 1.5;
             font-weight: 500;
             font-family: 'IBM Plex Sans', sans-serif;
           }
 
           p {
             text-align: center;
           }
 
           .separator {
             border: 1px solid #404040;
             width: 100%;
           }
 
           .button {
             all: unset;
             box-sizing: border-box;
             display: flex;
             justify-content: center;
             align-items: center;
             width: 100%;
             padding: 1.7rem;
             border-radius: 0.4rem;
             border: 1px solid transparent;
             background-color: #6d49ab;
             font-size: 1.6rem;
             line-height: 1.5;
           }
 
           .button.secondary {
             background-color: #1f1f1f;
             border-color: #ffffff;
           }
 
           .link {
             all: unset;
             box-sizing: border-box;
             display: flex;
             align-items: center;
           }
 
           .link-text {
             text-decoration-line: underline;
           }
 
           .logo-container {
             background-color: #0a0a0a;
             width: 4.2rem;
             height: 4.2rem;
             display: flex;
             justify-content: center;
             align-items: center;
             border-radius: 50%;
           }
 
           .logo {
             height: 2.6rem;
           }
 
           .arrow {
             width: 1.8rem;
             height: 1.8rem;
           }
         </style>
       </head>
       <body>
         <div></div>
         <section class="card">
           <section>
             <div class="logo-container">
               <img
                 src="/images/loading_logo.svg"
                 alt="Comm logo"
                 class="logo"
               />
             </div>
             <h1>Comm</h1>
           </section>
           <p>
             To join this community, download the Comm app and reopen this invite
             link
           </p>
           <div class="separator"></div>
           <section class="buttons">
             <a class="button" href="${stores.appStoreUrl}">Download Comm</a>
             <a class="button secondary" href="comm://invite/${secret}">
               Invite Link
             </a>
           </section>
         </section>
         <a class="link" href="https://comm.app/">
           <span class="link-text">Visit Comm’s website</span>
           <img
             src="/images/arrow_up_right.svg"
             alt="arrow up right"
             class="arrow"
           />
         </a>
       </body>
     </html>
   `);
 }
 
 export { websiteResponder, inviteResponder };