diff --git a/prefetch.bs b/prefetch.bs
index a151fe4..cd5e4e9 100644
--- a/prefetch.bs
+++ b/prefetch.bs
@@ -121,6 +121,8 @@ spec: html; urlPrefix: https://html.spec.whatwg.org/multipage/
         text: anonymization policy; url: sl-candidate-anonymization-policy
       for: speculative load candidate
         text: URL; url: sl-candidate-url
+    urlPrefix: webappapis.html
+      text: navigation and traversal task source
 spec: fetch; urlPrefix: https://fetch.spec.whatwg.org/
   type: dfn
     text: network partition key; url: network-partition-key
@@ -780,6 +782,33 @@ This section contains patches to [[NAVIGATION-TIMING]].
 
 This section contains patches to [[SERVICE-WORKERS]].
 
+<div algorithm="Service worker control">
+  Modify the definition of <a spec="SERVICE-WORKERS">controlled</a> as follows:
+
+  <blockquote>
+    When a [=service worker client=] has a non-null [=environment/active service worker=]<ins> whose [=environment/is navigational prefetch client=] is false</ins>, it is said to be <dfn noexport>controlled</dfn> by that [=environment/active service worker=].
+  </blockquote>
+</div>
+
+<div algorithm="Service Workers Update">
+  Modify the <a spec=SERVICE-WORKERS>Update</a> algorithm by changing the final step as follows:
+
+  1. Else,
+    1. Let |clients| be all [=service worker clients=] whose [=environment/active service worker=] is |worker|.
+    1. [=list/For each=] |client| of |clients|:
+      1. If |client| is not an [=environment settings object=], then [=iteration/continue=].
+      1. If |client|'s [=environment settings object/global object=] is not a {{Window}} object, then [=iteration/continue=].
+      1. [=Queue a global task=] on the [=navigation and traversal task source=] given |client|'s [=environment settings object/global object=] to perform the following steps:
+        1. Let |document| be |client|'s [=environment settings object/global object=]'s [=associated Document=].
+        1. [=list/For each=] |prefetchRecord| of |document|'s [=Document/prefetch records=]:
+          1. [=prefetch record/Cancel and discard=] |prefetchRecord| given |document|.
+
+      <p class="note">Clearing prefetch records in this way avoids a situation where a prefetched response was fetched with the pre-update service worker (<var ignore>newestWorker</var>), but then the navigation results in a client that is controlled by the post-update service worker (|worker|), which could have unexpected consequences for the web developer.</p>
+    1. Invoke <a spec=SERVICE-WORKERS>Install</a> with <var ignore>job</var>, |worker|, and <var ignore>registration</var>.
+</div>
+
+<hr>
+
 <div algorithm="Create Fetch Event and Dispatch">
   Modify <a spec="SERVICE-WORKERS">Create Fetch Event and Dispatch</a>'s step which sets {{FetchEvent/resultingClientId}} as follows: