diff --git a/api_docs/changelog.md b/api_docs/changelog.md
index ed240cdf5d..70d8c01337 100644
--- a/api_docs/changelog.md
+++ b/api_docs/changelog.md
@@ -20,6 +20,16 @@ format used by the Zulip server that they are interacting with.
 
 ## Changes in Zulip 8.0
 
+**Feature level 194**
+
+* [`GET /messages`](/api/get-messages),
+  [`GET /messages/matches_narrow`](/api/check-messages-match-narrow),
+  [`POST /message/flags/narrow`](/api/update-message-flags-for-narrow),
+  [`POST /register`](/api/register-queue):
+  For [search/narrow filters](/api/construct-narrow) with the `id`
+  operator, added support for encoding the message ID operand as either
+  a string or an integer. Previously, only string encoding was supported.
+
 **Feature level 193**
 
 * [`POST /messages/{message_id}/reactions`](/api/add-reaction),
diff --git a/api_docs/construct-narrow.md b/api_docs/construct-narrow.md
index 60a138258c..8e322e8c07 100644
--- a/api_docs/construct-narrow.md
+++ b/api_docs/construct-narrow.md
@@ -65,12 +65,33 @@ filters did.
 
 ## Narrows that use IDs
 
+### Message IDs
+
 The `near` and `id` operators, documented in the help center, use message
 IDs for their operands.
 
 * `near:12345`: Search messages around the message with ID `12345`.
 * `id:12345`: Search for only message with ID `12345`.
 
+The message ID operand for the `id` operator may be encoded as either a
+number or a string. The message ID operand for the `near` operator must
+be encoded as a string.
+
+**Changes**: Prior to Zulip 8.0 (feature level 194), the message ID
+operand for the `id` operator needed to be encoded as a string.
+
+
+```json
+[
+    {
+        "operator": "id",
+        "operand": 12345
+    }
+]
+```
+
+### Stream and user IDs
+
 There are a few additional narrow/search options (new in Zulip 2.1)
 that use either stream IDs or user IDs that are not documented in the
 help center because they are primarily useful to API clients:
diff --git a/version.py b/version.py
index 7b47b9c972..60bcda16d4 100644
--- a/version.py
+++ b/version.py
@@ -33,7 +33,7 @@ DESKTOP_WARNING_VERSION = "5.9.3"
 # Changes should be accompanied by documentation explaining what the
 # new level means in api_docs/changelog.md, as well as "**Changes**"
 # entries in the endpoint's documentation in `zulip.yaml`.
-API_FEATURE_LEVEL = 193
+API_FEATURE_LEVEL = 194
 
 # Bump the minor PROVISION_VERSION to indicate that folks should provision
 # only when going from an old version of the code to a newer version. Bump
diff --git a/web/src/message_fetch.js b/web/src/message_fetch.js
index f96925a4c7..21bfd0d3fe 100644
--- a/web/src/message_fetch.js
+++ b/web/src/message_fetch.js
@@ -140,13 +140,20 @@ function get_messages_success(data, opts) {
     process_result(data, opts);
 }
 
-// This function modifies the data.narrow filters to use user IDs
-// instead of emails string if it is supported. We currently don't set
-// or convert the emails string to user IDs directly into the Filter code
-// because doing so breaks the app in various modules that expect emails string.
+// This function modifies the data.narrow filters to use integer IDs
+// instead of strings if it is supported. We currently don't set or
+// convert user emails to user IDs directly in the Filter code
+// because doing so breaks the app in various modules that expect a
+// string of user emails.
 function handle_operators_supporting_id_based_api(data) {
     const operators_supporting_ids = new Set(["dm", "pm-with"]);
-    const operators_supporting_id = new Set(["sender", "group-pm-with", "stream", "dm-including"]);
+    const operators_supporting_id = new Set([
+        "id",
+        "stream",
+        "sender",
+        "group-pm-with",
+        "dm-including",
+    ]);
 
     if (data.narrow === undefined) {
         return data;
@@ -159,6 +166,12 @@ function handle_operators_supporting_id_based_api(data) {
         }
 
         if (operators_supporting_id.has(filter.operator)) {
+            if (filter.operator === "id") {
+                // The message ID may not exist locally,
+                // so send the filter to the server as is.
+                return filter;
+            }
+
             if (filter.operator === "stream") {
                 const stream_id = stream_data.get_stream_id(filter.operand);
                 if (stream_id !== undefined) {
diff --git a/zerver/lib/narrow.py b/zerver/lib/narrow.py
index 64acd4a2b7..c1b74e5046 100644
--- a/zerver/lib/narrow.py
+++ b/zerver/lib/narrow.py
@@ -751,11 +751,17 @@ def narrow_parameter(var_name: str, json: str) -> OptionalNarrowListT:
             return dict(operator=elem[0], operand=elem[1])
 
         if isinstance(elem, dict):
-            # Make sure to sync this list to frontend also when adding a new operator.
-            # that supports user IDs. Relevant code is located in web/src/message_fetch.js
-            # in handle_operators_supporting_id_based_api function where you will need to update
-            # operators_supporting_id, or operators_supporting_ids array.
-            operators_supporting_id = ["sender", "group-pm-with", "stream", "dm-including"]
+            # Make sure to sync this list to frontend also when adding a new operator that
+            # supports integer IDs. Relevant code is located in web/src/message_fetch.js
+            # in handle_operators_supporting_id_based_api function where you will need to
+            # update operators_supporting_id, or operators_supporting_ids array.
+            operators_supporting_id = [
+                "id",
+                "stream",
+                "sender",
+                "group-pm-with",
+                "dm-including",
+            ]
             operators_supporting_ids = ["pm-with", "dm"]
             operators_non_empty_operand = {"search"}
 
diff --git a/zerver/tests/test_message_fetch.py b/zerver/tests/test_message_fetch.py
index 6194e94352..23acc64e05 100644
--- a/zerver/tests/test_message_fetch.py
+++ b/zerver/tests/test_message_fetch.py
@@ -417,10 +417,14 @@ class NarrowBuilderTest(ZulipTestCase):
             "WHERE NOT (sender_id = %(sender_id_1)s AND recipient_id = %(recipient_id_1)s OR sender_id = %(sender_id_2)s AND recipient_id = %(recipient_id_2)s OR recipient_id IN (__[POSTCOMPILE_recipient_id_3]))",
         )
 
-    def test_add_term_using_id_operator(self) -> None:
+    def test_add_term_using_id_operator_integer(self) -> None:
         term = dict(operator="id", operand=555)
         self._do_add_term_test(term, "WHERE id = %(param_1)s")
 
+    def test_add_term_using_id_operator_string(self) -> None:
+        term = dict(operator="id", operand="555")
+        self._do_add_term_test(term, "WHERE id = %(param_1)s")
+
     def test_add_term_using_id_operator_invalid(self) -> None:
         term = dict(operator="id", operand="")
         self.assertRaises(BadNarrowOperatorError, self._build_query, term)
@@ -3412,10 +3416,11 @@ class GetOldMessagesTest(ZulipTestCase):
     def test_invalid_narrow_operand_in_dict(self) -> None:
         self.login("hamlet")
 
-        # str or int is required for "sender", "stream", "dm-including" and "group-pm-with" operators
+        # str or int is required for "id", "sender", "stream", "dm-including" and "group-pm-with"
+        # operators
         invalid_operands = [["1"], [2], None]
         error_msg = 'elem["operand"] is not a string or integer'
-        for operand in ["sender", "group-pm-with", "stream", "dm-including"]:
+        for operand in ["id", "sender", "stream", "dm-including", "group-pm-with"]:
             self.exercise_bad_narrow_operand_using_dict_api(operand, invalid_operands, error_msg)
 
         # str or int list is required for "dm" and "pm-with" operator
@@ -3432,7 +3437,7 @@ class GetOldMessagesTest(ZulipTestCase):
         # For others only str is acceptable
         invalid_operands = [2, None, [1]]
         error_msg = 'elem["operand"] is not a string'
-        for operand in ["is", "near", "has", "id"]:
+        for operand in ["is", "near", "has"]:
             self.exercise_bad_narrow_operand_using_dict_api(operand, invalid_operands, error_msg)
 
         # Disallow empty search terms