diff --git a/Cargo.lock b/Cargo.lock
index 4059ea8..a125dde 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1695,10 +1695,11 @@ checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
 [[package]]
 name = "streamstore"
 version = "0.1.0"
-source = "git+https://github.com/s2-streamstore/s2-sdk-rust.git?rev=35cf0314dbc230f8f96c860a2ca8f5217f68151e#35cf0314dbc230f8f96c860a2ca8f5217f68151e"
+source = "git+https://github.com/s2-streamstore/s2-sdk-rust.git?rev=88d6539cbec2165a79f07de4d3a13a9539b547d6#88d6539cbec2165a79f07de4d3a13a9539b547d6"
 dependencies = [
  "async-stream",
  "backon",
+ "bytes",
  "bytesize",
  "futures",
  "http",
@@ -1767,7 +1768,7 @@ dependencies = [
 [[package]]
 name = "sync_docs"
 version = "0.1.0"
-source = "git+https://github.com/s2-streamstore/s2-sdk-rust.git?rev=35cf0314dbc230f8f96c860a2ca8f5217f68151e#35cf0314dbc230f8f96c860a2ca8f5217f68151e"
+source = "git+https://github.com/s2-streamstore/s2-sdk-rust.git?rev=88d6539cbec2165a79f07de4d3a13a9539b547d6#88d6539cbec2165a79f07de4d3a13a9539b547d6"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/Cargo.toml b/Cargo.toml
index db7e089..064b3a1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,10 +19,13 @@ serde = { version = "1.0.214", features = ["derive"] }
 serde_json = "1.0.132"
 signal-hook = "0.3.17"
 signal-hook-tokio = { version = "0.3.1", features = ["futures-v0_3"] }
-streamstore = { git = "https://github.com/s2-streamstore/s2-sdk-rust.git", rev = "35cf0314dbc230f8f96c860a2ca8f5217f68151e" }
 thiserror = "1.0.67"
-tokio = { version = "*", features = ["full"] }
+tokio = { version = "1.41.1", features = ["full"] }
 tokio-stream = { version = "0.1.16", features = ["io-util"] }
 toml = "0.8.19"
 tracing = "0.1.40"
 tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
+
+[dependencies.streamstore]
+git = "https://github.com/s2-streamstore/s2-sdk-rust.git"
+rev = "88d6539cbec2165a79f07de4d3a13a9539b547d6"
diff --git a/src/main.rs b/src/main.rs
index a369a5d..553bee7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -15,7 +15,7 @@ use stream::{RecordStream, StreamService};
 use streamstore::{
     bytesize::ByteSize,
     client::{BasinClient, Client, ClientConfig, S2Endpoints, StreamClient},
-    types::{BasinInfo, BasinName, MeteredSize as _, ReadOutput, StreamInfo},
+    types::{BasinInfo, BasinName, FencingToken, MeteredSize as _, ReadOutput, StreamInfo},
     HeaderValue,
 };
 use tokio::{
@@ -210,6 +210,15 @@ enum StreamActions {
 
     /// Append records to a stream. Currently, only newline delimited records are supported.
     Append {
+        /// Enforce a fencing token which must have been previously set by a
+        /// `fence` command record.
+        #[arg(short = 'f', long)]
+        fencing_token: Option<FencingToken>,
+
+        /// Enforce that the sequence number issued to the first record matches.
+        #[arg(short = 's', long)]
+        match_seq_num: Option<u64>,
+
         /// Input newline delimited records to append from a file or stdin.
         /// All records are treated as plain text.
         /// Use "-" to read from stdin.
@@ -515,7 +524,11 @@ async fn run() -> Result<(), S2CliError> {
                     let next_seq_num = StreamService::new(stream_client).check_tail().await?;
                     println!("{}", next_seq_num);
                 }
-                StreamActions::Append { input } => {
+                StreamActions::Append {
+                    input,
+                    fencing_token,
+                    match_seq_num,
+                } => {
                     let stream_client = StreamClient::new(client_config, basin, stream);
                     let append_input_stream = RecordStream::new(
                         input
@@ -529,7 +542,7 @@ async fn run() -> Result<(), S2CliError> {
                         Signals::new([SIGTSTP, SIGINT, SIGTERM]).expect("valid signals");
 
                     let mut append_output_stream = StreamService::new(stream_client)
-                        .append_session(append_input_stream)
+                        .append_session(append_input_stream, fencing_token, match_seq_num)
                         .await?;
                     loop {
                         select! {
diff --git a/src/stream.rs b/src/stream.rs
index 20b869c..5550c7e 100644
--- a/src/stream.rs
+++ b/src/stream.rs
@@ -1,7 +1,7 @@
 use streamstore::{
-    batching::AppendRecordsBatchingStream,
+    batching::{AppendRecordsBatchingOpts, AppendRecordsBatchingStream},
     client::StreamClient,
-    types::{AppendOutput, ReadLimit, ReadOutput, ReadSessionRequest},
+    types::{AppendOutput, FencingToken, ReadLimit, ReadOutput, ReadSessionRequest},
     Streaming,
 };
 use tokio::io::AsyncBufRead;
@@ -72,9 +72,14 @@ impl StreamService {
     pub async fn append_session(
         &self,
         append_input_stream: RecordStream<Box<dyn AsyncBufRead + Send + Unpin>>,
+        fencing_token: Option<FencingToken>,
+        match_seq_num: Option<u64>,
     ) -> Result<Streaming<AppendOutput>, ServiceError> {
-        let append_record_stream =
-            AppendRecordsBatchingStream::new(append_input_stream, Default::default());
+        let opts = AppendRecordsBatchingOpts::default()
+            .with_fencing_token(fencing_token)
+            .with_match_seq_num(match_seq_num);
+
+        let append_record_stream = AppendRecordsBatchingStream::new(append_input_stream, opts);
 
         self.client
             .append_session(append_record_stream)