diff --git a/payjoin-cli/src/app/v2.rs b/payjoin-cli/src/app/v2.rs
index 8beb504c..942d7db5 100644
--- a/payjoin-cli/src/app/v2.rs
+++ b/payjoin-cli/src/app/v2.rs
@@ -7,7 +7,7 @@ use payjoin::bitcoin::consensus::encode::serialize_hex;
 use payjoin::bitcoin::psbt::Psbt;
 use payjoin::bitcoin::Amount;
 use payjoin::receive::v2::ActiveSession;
-use payjoin::send::RequestContext;
+use payjoin::send::{RequestContext, ResponseError};
 use payjoin::{bitcoin, Error, Uri};
 use tokio::signal;
 use tokio::sync::watch;
@@ -213,6 +213,7 @@ impl App {
     }
 
     async fn long_poll_post(&self, req_ctx: &mut payjoin::send::RequestContext) -> Result<Psbt> {
+        use payjoin::send::WellKnownError;
         loop {
             let (req, ctx) = req_ctx.extract_v2(self.config.ohttp_relay.clone())?;
             println!("Polling send request...");
@@ -232,6 +233,28 @@ impl App {
                     println!("No response yet.");
                     tokio::time::sleep(std::time::Duration::from_secs(5)).await;
                 }
+                Err(ResponseError::WellKnown(WellKnownError::VersionUnsupported {
+                    message,
+                    supported,
+                })) => {
+                    if supported.contains(&1) {
+                        let (req, ctx) = req_ctx.clone().extract_v1()?;
+                        println!("Polling send request...");
+                        let http = http_agent()?;
+                        let response = http
+                            .post(req.url)
+                            .header("Content-Type", "text/plain")
+                            .body(req.body)
+                            .send()
+                            .await
+                            .map_err(map_reqwest_err)?;
+
+                        return Ok(
+                            ctx.process_response(&mut response.bytes().await?.to_vec().as_slice())?
+                        );
+                    }
+                    return Err(anyhow!("Response error: {}", message));
+                }
                 Err(re) => {
                     println!("{}", re);
                     log::debug!("{:?}", re);
diff --git a/payjoin/src/send/mod.rs b/payjoin/src/send/mod.rs
index 175b3dce..36dc0136 100644
--- a/payjoin/src/send/mod.rs
+++ b/payjoin/src/send/mod.rs
@@ -32,7 +32,7 @@ use bitcoin::secp256k1::rand;
 #[cfg(feature = "v2")]
 use bitcoin::secp256k1::PublicKey;
 use bitcoin::{FeeRate, Script, ScriptBuf, Sequence, TxOut, Weight};
-pub use error::{CreateRequestError, ResponseError, ValidationError};
+pub use error::{CreateRequestError, ResponseError, ValidationError, WellKnownError};
 pub(crate) use error::{InternalCreateRequestError, InternalValidationError};
 #[cfg(feature = "v2")]
 use serde::{
@@ -557,6 +557,7 @@ impl ContextV2 {
         let mut body = match response.status() {
             http::StatusCode::OK => response.body().to_vec(),
             http::StatusCode::ACCEPTED => return Ok(None),
+            http::StatusCode::BAD_REQUEST => return Ok(None), // TODO return properl
             _ => return Err(InternalValidationError::UnexpectedStatusCode)?,
         };
         let psbt = crate::v2::decrypt_message_b(&mut body, self.e)