diff --git a/android/Omnivore/app/src/main/java/app/omnivore/omnivore/networking/HighlightMutations.kt b/android/Omnivore/app/src/main/java/app/omnivore/omnivore/networking/HighlightMutations.kt
index 5329392a1..46f988ec4 100644
--- a/android/Omnivore/app/src/main/java/app/omnivore/omnivore/networking/HighlightMutations.kt
+++ b/android/Omnivore/app/src/main/java/app/omnivore/omnivore/networking/HighlightMutations.kt
@@ -4,8 +4,10 @@ import android.util.Log
 import app.omnivore.omnivore.graphql.generated.CreateHighlightMutation
 import app.omnivore.omnivore.graphql.generated.DeleteHighlightMutation
 import app.omnivore.omnivore.graphql.generated.MergeHighlightMutation
+import app.omnivore.omnivore.graphql.generated.UpdateHighlightMutation
 import app.omnivore.omnivore.graphql.generated.type.CreateHighlightInput
 import app.omnivore.omnivore.graphql.generated.type.MergeHighlightInput
+import app.omnivore.omnivore.graphql.generated.type.UpdateHighlightInput
 import app.omnivore.omnivore.models.Highlight
 import com.apollographql.apollo3.api.Optional
 import com.google.gson.Gson
@@ -29,6 +31,18 @@ data class CreateHighlightParams(
   )
 }
 
+data class UpdateHighlightParams(
+  val highlightId: String?,
+  val `annotation`: String?,
+  val sharedAt: String?,
+) {
+  fun asUpdateHighlightInput() = UpdateHighlightInput(
+    annotation = Optional.presentIfNotNull(`annotation`),
+    highlightId = highlightId ?: "",
+    sharedAt = Optional.presentIfNotNull(sharedAt)
+  )
+}
+
 data class MergeHighlightsParams(
   val shortId: String?,
   val id: String?,
@@ -74,6 +88,17 @@ suspend fun Networker.deleteHighlights(highlightIDs: List<String>): Boolean {
   return !hasFailure
 }
 
+suspend fun Networker.updateWebHighlight(jsonString: String): Boolean {
+  val input = Gson().fromJson(jsonString, UpdateHighlightParams::class.java).asUpdateHighlightInput()
+  return updateHighlight(input)
+}
+
+suspend fun Networker.updateHighlight(input: UpdateHighlightInput): Boolean {
+  val result = authenticatedApolloClient().mutation(UpdateHighlightMutation(input)).execute()
+  Log.d("Network", "update highlight result: $result")
+  return result.data?.updateHighlight?.onUpdateHighlightSuccess?.highlight != null
+}
+
 suspend fun Networker.mergeWebHighlights(jsonString: String): Boolean {
   val input = Gson().fromJson(jsonString, MergeHighlightsParams::class.java).asMergeHighlightInput()
   return mergeHighlights(input)
diff --git a/android/Omnivore/app/src/main/java/app/omnivore/omnivore/ui/reader/PDFReaderViewModel.kt b/android/Omnivore/app/src/main/java/app/omnivore/omnivore/ui/reader/PDFReaderViewModel.kt
index 04eb40d1a..4f38ae3ca 100644
--- a/android/Omnivore/app/src/main/java/app/omnivore/omnivore/ui/reader/PDFReaderViewModel.kt
+++ b/android/Omnivore/app/src/main/java/app/omnivore/omnivore/ui/reader/PDFReaderViewModel.kt
@@ -9,6 +9,7 @@ import androidx.lifecycle.viewModelScope
 import app.omnivore.omnivore.DatastoreRepository
 import app.omnivore.omnivore.graphql.generated.type.CreateHighlightInput
 import app.omnivore.omnivore.graphql.generated.type.MergeHighlightInput
+import app.omnivore.omnivore.graphql.generated.type.UpdateHighlightInput
 import app.omnivore.omnivore.models.LinkedItem
 import app.omnivore.omnivore.networking.*
 import com.apollographql.apollo3.api.Optional
@@ -152,8 +153,16 @@ class PDFReaderViewModel @Inject constructor(
       annotation.customData = JSONObject().put("omnivoreHighlight", it)
     }
 
-    // TODO: Sync update with data service
-
+    // Sync update with data service
+    viewModelScope.launch {
+      val input = UpdateHighlightInput(
+        annotation = Optional.presentIfNotNull(note),
+        highlightId = pluckHighlightID(annotation) ?: "",
+        sharedAt = Optional.Absent
+      )
+      networker.updateHighlight(input)
+      Log.d("network", "updated $annotation")
+    }
   }
 
   fun deleteHighlight(annotation: Annotation) {
diff --git a/android/Omnivore/app/src/main/java/app/omnivore/omnivore/ui/reader/WebReaderViewModel.kt b/android/Omnivore/app/src/main/java/app/omnivore/omnivore/ui/reader/WebReaderViewModel.kt
index e1e693d56..57e1b72d3 100644
--- a/android/Omnivore/app/src/main/java/app/omnivore/omnivore/ui/reader/WebReaderViewModel.kt
+++ b/android/Omnivore/app/src/main/java/app/omnivore/omnivore/ui/reader/WebReaderViewModel.kt
@@ -77,6 +77,10 @@ class WebReaderViewModel @Inject constructor(
       }
       "updateHighlight" -> {
         Log.d("Loggo", "receive update highlight action: $jsonString")
+        viewModelScope.launch {
+          val isHighlightUpdateSynced = networker.updateWebHighlight(jsonString)
+          Log.d("Network", "isHighlightUpdateSynced = $isHighlightUpdateSynced")
+        }
       }
       "articleReadingProgress" -> {
         viewModelScope.launch {