one more for privacy deprecation warning

Signed-off-by: Sally MacFarlane <macfarla.github@gmail.com>

docs/private-networks/how-to/send-transactions/concurrent-private-transactions.md

@@ -6,7 +6,13 @@ tags:
   - private networks
 ---
 
-# Send concurrent private transactions
+# Send concurrent private transactions (Deprecated)
+
+:::caution
+
+Tessera-based privacy is deprecated in Besu version 24.11.0 and later. Please read this [blog post](https://www.lfdecentralizedtrust.org/blog/sunsetting-tessera-and-simplifying-hyperledger-besu) for more context on the rationale behind this decision as well as alternative options.
+
+:::
 
 Private transaction processing involves two transactions, the private transaction and the [privacy marker transaction (PMT)](../../concepts/privacy/private-transactions/processing.md). The private transaction and the PMT each have their own [nonce](../../concepts/privacy/private-transactions/index.md#nonces).