diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# Version [0.12.1.0](https://github.com/blockfrost/blockfrost-haskell/compare/api-0.12.0.0...api-0.12.1.0) (2024-09-25)
+
+* Fix return type of `/txs/:hash/cbor` endpoint from `[TransactionCBOR]` to `TransactionCBOR`.
+
 # Version [0.12.0.0](https://github.com/blockfrost/blockfrost-haskell/compare/api-0.11.0.0...api-0.12.0.0) (2024-09-19)
 
 * Additions
diff --git a/blockfrost-api.cabal b/blockfrost-api.cabal
--- a/blockfrost-api.cabal
+++ b/blockfrost-api.cabal
@@ -1,6 +1,6 @@
 cabal-version:       2.2
 name:                blockfrost-api
-version:             0.12.0.0
+version:             0.12.1.0
 synopsis:            API definitions for blockfrost.io
 description:         Core types and Servant API description
 homepage:            https://github.com/blockfrost/blockfrost-haskell
diff --git a/src/Blockfrost/API/Cardano/Transactions.hs b/src/Blockfrost/API/Cardano/Transactions.hs
--- a/src/Blockfrost/API/Cardano/Transactions.hs
+++ b/src/Blockfrost/API/Cardano/Transactions.hs
@@ -89,7 +89,7 @@
         :> Description "Obtain the CBOR serialized transaction."
         :> Capture "hash" TxHash
         :> "cbor"
-        :> Get '[JSON] [TransactionCBOR]
+        :> Get '[JSON] TransactionCBOR
     , _txMetadataCBOR
         :: route
         :- Summary "Transaction metadata in CBOR"