diff --git a/Cargo.toml b/Cargo.toml
index 64839198c..c1ac2d989 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -78,7 +78,8 @@ ruma = { path = "/home/work/code/ruma/crates/ruma", features = [
     "unstable-msc4222",
     "unstable-msc4278",
     "unstable-msc4286",
-    "unstable-msc4306"
+    "unstable-msc4306",
+    "unstable-msc4308"
 ] }
 sentry = "0.36.0"
 sentry-tracing = "0.36.0"
diff --git a/crates/matrix-sdk-base/src/room/call.rs b/crates/matrix-sdk-base/src/room/call.rs
index 34d789e63..ccf075daf 100644
--- a/crates/matrix-sdk-base/src/room/call.rs
+++ b/crates/matrix-sdk-base/src/room/call.rs
@@ -144,6 +144,7 @@ mod tests {
                         focus_active,
                         foci_preferred,
                         Some(timestamp(minutes_ago)),
+                        None,
                     ),
                     CallMemberStateKey::new(user_id.to_owned(), Some(member_id), false),
                 )
diff --git a/crates/matrix-sdk/CHANGELOG.md b/crates/matrix-sdk/CHANGELOG.md
index 71a66492e..975a765f3 100644
--- a/crates/matrix-sdk/CHANGELOG.md
+++ b/crates/matrix-sdk/CHANGELOG.md
@@ -8,6 +8,10 @@ All notable changes to this project will be documented in this file.
 
 ### Features
 
+- `Client::fetch_thread_subscriptions` implements support for the companion endpoint of the
+  experimental MSC4308, allowing to fetch thread subscriptions for a given range, as specified by
+  the MSC.
+  ([#XXXX](https://github.com/matrix-org/matrix-rust-sdk/pull/XXXX))
 - `Room::enable_encryption` and `Room::enable_encryption_with_state_event_encryption` will poll
   the encryption state for up to 3 seconds, rather than checking once after a single sync has
   completed.
diff --git a/crates/matrix-sdk/src/client/mod.rs b/crates/matrix-sdk/src/client/mod.rs
index 0337ea01b..7275d28ba 100644
--- a/crates/matrix-sdk/src/client/mod.rs
+++ b/crates/matrix-sdk/src/client/mod.rs
@@ -61,6 +61,7 @@ use ruma::{
             room::create_room,
             session::login::v3::DiscoveryInfo,
             sync::sync_events,
+            threads::get_thread_subscriptions_changes,
             uiaa,
             user_directory::search_users,
         },
@@ -2885,6 +2886,25 @@ impl Client {
             ThreadingSupport::Disabled => false,
         }
     }
+
+    /// Fetch thread subscriptions changes between `from` and up to `to`.
+    ///
+    /// The `limit` optional parameter can be used to limit the number of
+    /// entries in a response. It can also be overridden by the server, if
+    /// it's deemed too large.
+    pub async fn fetch_thread_subscriptions(
+        &self,
+        from: Option<String>,
+        to: Option<String>,
+        limit: Option<UInt>,
+    ) -> Result<get_thread_subscriptions_changes::unstable::Response> {
+        let request = assign!(get_thread_subscriptions_changes::unstable::Request::new(), {
+            from,
+            to,
+            limit,
+        });
+        Ok(self.send(request).await?)
+    }
 }
 
 #[cfg(any(feature = "testing", test))]
diff --git a/crates/matrix-sdk/src/test_utils/mocks/mod.rs b/crates/matrix-sdk/src/test_utils/mocks/mod.rs
index fccdb4d3b..e877dd176 100644
--- a/crates/matrix-sdk/src/test_utils/mocks/mod.rs
+++ b/crates/matrix-sdk/src/test_utils/mocks/mod.rs
@@ -30,7 +30,13 @@ use matrix_sdk_test::{
 };
 use percent_encoding::{AsciiSet, CONTROLS};
 use ruma::{
-    api::client::{receipt::create_receipt::v3::ReceiptType, room::Visibility},
+    api::client::{
+        receipt::create_receipt::v3::ReceiptType,
+        room::Visibility,
+        threads::get_thread_subscriptions_changes::unstable::{
+            ThreadSubscription, ThreadUnsubscription,
+        },
+    },
     device_id,
     directory::PublicRoomsChunk,
     encryption::{CrossSigningKey, DeviceKeys, OneTimeKey},
@@ -1346,8 +1352,8 @@ impl MatrixMockServer {
         self.mock_endpoint(mock, AuthedMediaThumbnailEndpoint).expect_default_access_token()
     }
 
-    /// Create a prebuilt mock for the endpoint used to get a thread
-    /// subscription in a given room.
+    /// Create a prebuilt mock for the endpoint used to get a single thread
+    /// subscription status in a given room.
     pub fn mock_get_thread_subscription(&self) -> MockEndpoint<'_, GetThreadSubscriptionEndpoint> {
         let mock = Mock::given(method("GET"));
         self.mock_endpoint(mock, GetThreadSubscriptionEndpoint::default())
@@ -1427,6 +1433,17 @@ impl MatrixMockServer {
         let mock = Mock::given(method("GET")).and(path("/_matrix/federation/v1/version"));
         self.mock_endpoint(mock, FederationVersionEndpoint)
     }
+
+    /// Create a prebuilt mock for the endpoint used to get all thread
+    /// subscriptions across all rooms.
+    pub fn mock_get_thread_subscriptions(
+        &self,
+    ) -> MockEndpoint<'_, GetThreadSubscriptionsEndpoint> {
+        let mock = Mock::given(method("GET"))
+            .and(path_regex(r"^/_matrix/client/unstable/io.element.msc4308/thread_subscriptions$"));
+        self.mock_endpoint(mock, GetThreadSubscriptionsEndpoint::default())
+            .expect_default_access_token()
+    }
 }
 
 /// A specification for a push rule ID.
@@ -4136,3 +4153,56 @@ impl<'a> MockEndpoint<'a, FederationVersionEndpoint> {
         self.respond_with(ResponseTemplate::new(200).set_body_json(response_body))
     }
 }
+
+/// A prebuilt mock for `GET ^/_matrix/client/v3/thread_subscriptions`.
+#[derive(Default)]
+pub struct GetThreadSubscriptionsEndpoint {
+    /// New thread subscriptions per (room id, thread root event id).
+    subscribed: BTreeMap<OwnedRoomId, BTreeMap<OwnedEventId, ThreadSubscription>>,
+    /// New thread unsubscriptions per (room id, thread root event id).
+    unsubscribed: BTreeMap<OwnedRoomId, BTreeMap<OwnedEventId, ThreadUnsubscription>>,
+}
+
+impl<'a> MockEndpoint<'a, GetThreadSubscriptionsEndpoint> {
+    /// Add a single thread subscription to the response.
+    pub fn add_subscription(
+        mut self,
+        room_id: OwnedRoomId,
+        thread_root: OwnedEventId,
+        subscription: ThreadSubscription,
+    ) -> Self {
+        self.endpoint.subscribed.entry(room_id).or_default().insert(thread_root, subscription);
+        self
+    }
+
+    /// Add a single thread unsubscription to the response.
+    pub fn add_unsubcription(
+        mut self,
+        room_id: OwnedRoomId,
+        thread_root: OwnedEventId,
+        unsubscription: ThreadUnsubscription,
+    ) -> Self {
+        self.endpoint.unsubscribed.entry(room_id).or_default().insert(thread_root, unsubscription);
+        self
+    }
+
+    /// Match the `from` query parameter to a given value.
+    pub fn match_from(self, from: &str) -> Self {
+        Self { mock: self.mock.and(query_param("from", from)), ..self }
+    }
+    /// Match the `to` query parameter to a given value.
+    pub fn match_to(self, to: &str) -> Self {
+        Self { mock: self.mock.and(query_param("to", to)), ..self }
+    }
+
+    /// Returns a successful response with the given thread subscriptions, and
+    /// "end" parameter to be used in the next query.
+    pub fn ok(self, end: Option<String>) -> MatrixMock<'a> {
+        let response_body = json!({
+            "subscribed": self.endpoint.subscribed,
+            "unsubscribed": self.endpoint.unsubscribed,
+            "end": end,
+        });
+        self.respond_with(ResponseTemplate::new(200).set_body_json(response_body))
+    }
+}
diff --git a/crates/matrix-sdk/tests/integration/client.rs b/crates/matrix-sdk/tests/integration/client.rs
index 621cae0ad..ebe5a2756 100644
--- a/crates/matrix-sdk/tests/integration/client.rs
+++ b/crates/matrix-sdk/tests/integration/client.rs
@@ -1,4 +1,4 @@
-use std::{collections::BTreeMap, time::Duration};
+use std::{collections::BTreeMap, ops::Not as _, time::Duration};
 
 use assert_matches2::{assert_let, assert_matches};
 use eyeball_im::VectorDiff;
@@ -46,10 +46,11 @@ use ruma::{
         room::{history_visibility::HistoryVisibility, member::MembershipState},
         AnyInitialStateEvent,
     },
+    owned_event_id, owned_room_id,
     room::JoinRule,
     room_id,
     serde::Raw,
-    user_id, OwnedUserId,
+    uint, user_id, OwnedUserId,
 };
 use serde_json::{json, Value as JsonValue};
 use stream_assert::{assert_next_matches, assert_pending};
@@ -1516,3 +1517,66 @@ async fn test_server_vendor_info_with_missing_fields() {
     assert_eq!(server_info.server_name, "unknown");
     assert_eq!(server_info.version, "unknown");
 }
+
+#[async_test]
+async fn test_fetch_thread_subscriptions() {
+    use ruma::api::client::threads::get_thread_subscriptions_changes::unstable::{
+        ThreadSubscription, ThreadUnsubscription,
+    };
+
+    let server = MatrixMockServer::new().await;
+    let client = server.client_builder().build().await;
+
+    let room1 = owned_room_id!("!room1:example.com");
+    let room2 = owned_room_id!("!room2:example.com");
+    let room3 = owned_room_id!("!room3:example.com");
+
+    let thread1 = owned_event_id!("$thread1:example.com");
+    let thread2 = owned_event_id!("$thread2:example.com");
+    let thread3 = owned_event_id!("$thread3:example.com");
+
+    server
+        .mock_get_thread_subscriptions()
+        .match_from("from")
+        .match_to("to")
+        .add_subscription(
+            room1.clone(),
+            thread1.clone(),
+            ThreadSubscription { automatic: true, bump_stamp: uint!(42) },
+        )
+        .add_subscription(
+            room2.clone(),
+            thread2.clone(),
+            ThreadSubscription { automatic: false, bump_stamp: uint!(7) },
+        )
+        .add_unsubcription(
+            room3.clone(),
+            thread3.clone(),
+            ThreadUnsubscription { bump_stamp: uint!(13) },
+        )
+        .ok(Some("next_batch_token".to_owned()))
+        .mount()
+        .await;
+
+    let response = client
+        .fetch_thread_subscriptions(Some("from".to_owned()), Some("to".to_owned()), None)
+        .await
+        .unwrap();
+
+    assert_eq!(response.end.as_deref(), Some("next_batch_token"));
+
+    assert_eq!(response.subscribed.len(), 2);
+
+    let s1 = &response.subscribed[&room1][&thread1];
+    assert!(s1.automatic);
+    assert_eq!(s1.bump_stamp, uint!(42));
+
+    let s2 = &response.subscribed[&room2][&thread2];
+    assert!(s2.automatic.not());
+    assert_eq!(s2.bump_stamp, uint!(7));
+
+    assert_eq!(response.unsubscribed.len(), 1);
+
+    let u = &response.unsubscribed[&room3][&thread3];
+    assert_eq!(u.bump_stamp, uint!(13));
+}