diff --git a/crates/matrix-sdk/src/encryption/backups/mod.rs b/crates/matrix-sdk/src/encryption/backups/mod.rs
index 0e7800ff9dc..f7b6bc921bc 100644
--- a/crates/matrix-sdk/src/encryption/backups/mod.rs
+++ b/crates/matrix-sdk/src/encryption/backups/mod.rs
@@ -403,7 +403,7 @@ impl Backups {
     /// backup exists - instead use [`Self::fetch_exists_on_server`]. This
     /// method is useful when performance is more important than guaranteed
     /// accuracy, such as when classifying UTDs.
-    pub async fn fast_exists_on_server(&self) -> Result<bool, Error> {
+    pub async fn exists_on_server(&self) -> Result<bool, Error> {
         // If we have an answer cached, return it immediately
         if let Some(cached_value) = self.client.inner.e2ee.backup_state.backup_exists_on_server() {
             return Ok(cached_value);
@@ -660,6 +660,9 @@ impl Backups {
             }
         };
 
+        // If the request succeeded, the backup is gone. If it failed, we are not really
+        // sure what the backup state is. Either way, clear the cache so we check next
+        // time we need to know.
         self.client.inner.e2ee.backup_state.clear_backup_exists_on_server();
 
         ret
@@ -1222,7 +1225,7 @@ mod test {
     }
 
     #[async_test]
-    async fn test_when_a_backup_exists_then_fast_exists_on_server_returns_true() {
+    async fn test_when_a_backup_exists_then_exists_on_server_returns_true() {
         let server = MatrixMockServer::new().await;
         let client = server.client_builder().build().await;
 
@@ -1231,7 +1234,7 @@ mod test {
         let exists = client
             .encryption()
             .backups()
-            .fast_exists_on_server()
+            .exists_on_server()
             .await
             .expect("We should be able to check if backups exist on the server");
 
@@ -1239,7 +1242,7 @@ mod test {
     }
 
     #[async_test]
-    async fn test_when_no_backup_exists_then_fast_exists_on_server_returns_false() {
+    async fn test_when_no_backup_exists_then_exists_on_server_returns_false() {
         let server = MatrixMockServer::new().await;
         let client = server.client_builder().build().await;
 
@@ -1248,7 +1251,7 @@ mod test {
         let exists = client
             .encryption()
             .backups()
-            .fast_exists_on_server()
+            .exists_on_server()
             .await
             .expect("We should be able to check if backups exist on the server");
 
@@ -1256,7 +1259,7 @@ mod test {
     }
 
     #[async_test]
-    async fn test_when_server_returns_an_error_then_fast_exists_on_server_returns_an_error() {
+    async fn test_when_server_returns_an_error_then_exists_on_server_returns_an_error() {
         let server = MatrixMockServer::new().await;
         let client = server.client_builder().build().await;
 
@@ -1264,7 +1267,7 @@ mod test {
             let _scope =
                 server.mock_room_keys_version().error429().expect(1).mount_as_scoped().await;
 
-            client.encryption().backups().fast_exists_on_server().await.expect_err(
+            client.encryption().backups().exists_on_server().await.expect_err(
                 "If the /version endpoint returns a non 404 error we should throw an error",
             );
         }
@@ -1273,14 +1276,14 @@ mod test {
             let _scope =
                 server.mock_room_keys_version().error404().expect(1).mount_as_scoped().await;
 
-            client.encryption().backups().fast_exists_on_server().await.expect_err(
+            client.encryption().backups().exists_on_server().await.expect_err(
                 "If the /version endpoint returns a non-Matrix 404 error we should throw an error",
             );
         }
     }
 
     #[async_test]
-    async fn test_repeated_calls_to_fast_exists_on_server_do_not_make_additional_requests() {
+    async fn test_repeated_calls_to_exists_on_server_do_not_make_additional_requests() {
         let server = MatrixMockServer::new().await;
         let client = server.client_builder().build().await;
 
@@ -1289,13 +1292,13 @@ mod test {
 
         let backups = client.encryption().backups();
 
-        // Call fast_exists_on_server several times
-        backups.fast_exists_on_server().await.unwrap();
-        backups.fast_exists_on_server().await.unwrap();
-        backups.fast_exists_on_server().await.unwrap();
+        // Call exists_on_server several times
+        backups.exists_on_server().await.unwrap();
+        backups.exists_on_server().await.unwrap();
+        backups.exists_on_server().await.unwrap();
 
         let exists = backups
-            .fast_exists_on_server()
+            .exists_on_server()
             .await
             .expect("We should be able to check if backups exist on the server");
 
@@ -1305,7 +1308,7 @@ mod test {
     }
 
     #[async_test]
-    async fn test_adding_a_backup_invalidates_fast_exists_on_server_cache() {
+    async fn test_adding_a_backup_invalidates_exists_on_server_cache() {
         let server = MatrixMockServer::new().await;
         let client = server.client_builder().build().await;
         let backups = client.encryption().backups();
@@ -1313,8 +1316,8 @@ mod test {
         {
             let _scope = server.mock_room_keys_version().none().expect(1).mount_as_scoped().await;
 
-            // Call fast_exists_on_server to fill the cache
-            let exists = backups.fast_exists_on_server().await.unwrap();
+            // Call exists_on_server to fill the cache
+            let exists = backups.exists_on_server().await.unwrap();
             assert!(!exists, "No backup exists at this point");
         }
 
@@ -1324,7 +1327,7 @@ mod test {
 
         server.mock_room_keys_version().exists().expect(1).mount().await;
         let exists = backups
-            .fast_exists_on_server()
+            .exists_on_server()
             .await
             .expect("We should be able to check if backups exist on the server");
 
@@ -1332,7 +1335,7 @@ mod test {
     }
 
     #[async_test]
-    async fn test_removing_a_backup_invalidates_fast_exists_on_server_cache() {
+    async fn test_removing_a_backup_invalidates_exists_on_server_cache() {
         let server = MatrixMockServer::new().await;
         let client = server.client_builder().build().await;
         let backups = client.encryption().backups();
@@ -1340,8 +1343,8 @@ mod test {
         {
             let _scope = server.mock_room_keys_version().exists().expect(1).mount_as_scoped().await;
 
-            // Call fast_exists_on_server to fill the cache
-            let exists = backups.fast_exists_on_server().await.unwrap();
+            // Call exists_on_server to fill the cache
+            let exists = backups.exists_on_server().await.unwrap();
             assert!(exists, "A backup exists at this point");
         }
 
@@ -1351,7 +1354,7 @@ mod test {
 
         server.mock_room_keys_version().none().expect(1).mount().await;
         let exists = backups
-            .fast_exists_on_server()
+            .exists_on_server()
             .await
             .expect("We should be able to check if backups exist on the server");