diff --git a/CHANGELOG.md b/CHANGELOG.md
index 84f4d88..2019314 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 0.4.1 - Mapping for Typename on loading
+
+Add `readTypedScriptWith`, which allows to load scripts having been written with an older version of `ply`, see _Mapping for Typename_ section in README.md for example.
+
 # 0.4.0 -  Direct 'TypedScript' access and usage, and add Rational instances
 
 - Add `Ply.Core.Unsafe` to the public API, which allows direct access to `TypedScript`.
diff --git a/README.md b/README.md
index 7b44b11..8f947f0 100644
--- a/README.md
+++ b/README.md
@@ -157,6 +157,22 @@ main = do
 
 > Aside: Notice how I didn't use type applications, it got inferred from the surrounding context!
 
+### Mapping for Typename
+
+The way `ply` stores scripts parameters type names has changed at some point. Previously `Typename` was stored without package qualifiers, so if you need to load scripts serialized quite a while ago, you might need a way to convert type names upon doing that. Use `readTypedScriptWith`, which takes an additional mapping like as following:
+
+```haskell
+paramMapping :: Text -> Text
+paramMapping = \case
+  "Address" -> "PlutusLedgerApi.V1.Address:Address"
+  "Credential" -> "PlutusLedgerApi.V1.Credential:Credential"
+  "CurrencySymbol" -> "PlutusLedgerApi.V1.Value:CurrencySymbol"
+  "ValidatorHash" -> "PlutusLedgerApi.V1.Scripts:ScriptHash"
+  "TokenName" -> "PlutusLedgerApi.V1.Value:TokenName"
+  "Integer" -> "GHC.Num.Integer:Integer"
+  others -> others
+```
+
 ## Building a TypedScript directly from Plutarch
 
 `Ply.Plutarch.writeTypedScript` is essentially a wrapper around `Ply.Plutarch.mkEnvelope`, which is then a wrapper around `Ply.Plutarch.toTypedScript`.
diff --git a/ply-core/src/Ply.hs b/ply-core/src/Ply.hs
index d74622e..5e452e6 100644
--- a/ply-core/src/Ply.hs
+++ b/ply-core/src/Ply.hs
@@ -8,6 +8,7 @@ module Ply (
   typeName,
   PlyArg,
   readTypedScript,
+  readTypedScriptWith,
   getPlutusVersion,
   (#),
   (#$),
@@ -17,7 +18,7 @@ module Ply (
 
 import Ply.Core.Apply ((#), (#!), (#$), (#$!))
 import Ply.Core.Class (PlyArg)
-import Ply.Core.TypedReader (readTypedScript)
+import Ply.Core.TypedReader (readTypedScript, readTypedScriptWith)
 import Ply.Core.Typename (typeName)
 import Ply.Core.Types (
   ScriptReaderException (..),
diff --git a/ply-core/src/Ply/Core/TypedReader.hs b/ply-core/src/Ply/Core/TypedReader.hs
index 6fa7cdc..21c07f8 100644
--- a/ply-core/src/Ply/Core/TypedReader.hs
+++ b/ply-core/src/Ply/Core/TypedReader.hs
@@ -1,10 +1,16 @@
 {-# LANGUAGE UnboxedTuples #-}
 {-# LANGUAGE UndecidableInstances #-}
 
-module Ply.Core.TypedReader (TypedReader, readTypedScript, mkTypedScript, typedScriptToEnvelope) where
+module Ply.Core.TypedReader (
+  TypedReader,
+  readTypedScript,
+  readTypedScriptWith,
+  typedScriptToEnvelope,
+) where
 
 import Control.Exception (throwIO)
 import Control.Monad (unless)
+import Data.Coerce (coerce)
 import Data.Proxy (Proxy (Proxy))
 import Data.Text (Text)
 
@@ -15,6 +21,7 @@ import Ply.Core.Types (
   ScriptRole (ValidatorRole),
   TypedScript (TypedScriptConstr),
   TypedScriptEnvelope (..),
+  Typename (Typename),
  )
 import Ply.Core.Unsafe (unsafeUnTypedScript)
 
@@ -27,19 +34,21 @@ type TypedReader rl params =
   , ReifyTypenames params
   )
 
--- | Pure function to parse a 'TypedScript' from a 'TypedScriptEnvelope'.
-mkTypedScript ::
+mkTypedScriptWith ::
   forall rl params.
   TypedReader rl params =>
+  (Text -> Text) ->
   TypedScriptEnvelope ->
   Either ScriptReaderException (TypedScript rl params)
-mkTypedScript (TypedScriptEnvelope ver rol params _ prog) = do
+mkTypedScriptWith mapping (TypedScriptEnvelope ver rol params _ prog) = do
   unless (rol == reifyRole (Proxy @rl)) . Left $ ScriptRoleError ValidatorRole rol
   let expectedParams = reifyTypenames $ Proxy @params
-  unless (expectedParams == params) . Left $ ScriptTypeError expectedParams params
+  let actualParams = coerce mapping <$> params
+  unless (expectedParams == actualParams) . Left $ ScriptTypeError expectedParams actualParams
   pure $ TypedScriptConstr ver prog
 
-{- | Read and verify a 'TypedScript' from given filepath.
+{- | Read and verify a 'TypedScript' from given filepath. If you need to adjust type names use
+'readTypedScriptWith' instead.
 
 The user is responsible for choosing the "correct" 'ScriptRole' and script parameters, probably
 with type applications. The reader will then use this information to parse the file and verify
@@ -50,7 +59,21 @@ readTypedScript ::
   -- | File path where the typed script file is located.
   FilePath ->
   IO (TypedScript r params)
-readTypedScript p = readEnvelope p >>= either throwIO pure . mkTypedScript
+readTypedScript = readTypedScriptWith id
+
+{- | Like 'readTypedScript', but takes a mapper @(Text -> Text) @ for type names of a script
+parameters. It might be useful if your script have been serialized with an older version of
+@ply@, which would write type constructor name, or using old-style ledger types. Mapping
+applies to @Typename@'s coming in the envelop.
+-}
+readTypedScriptWith ::
+  TypedReader r params =>
+  -- | Mapping for type names of script parameters.
+  (Text -> Text) ->
+  -- | File path where the typed script file is located.
+  FilePath ->
+  IO (TypedScript r params)
+readTypedScriptWith mapping p = readEnvelope p >>= either throwIO pure . mkTypedScriptWith mapping
 
 -- | Converting a 'TypedScript' into a 'TypedScriptEnvelope', given the description and the script.
 typedScriptToEnvelope ::
diff --git a/ply-core/src/Ply/Core/Typename.hs b/ply-core/src/Ply/Core/Typename.hs
index b1a5f29..6a5da3e 100644
--- a/ply-core/src/Ply/Core/Typename.hs
+++ b/ply-core/src/Ply/Core/Typename.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE AllowAmbiguousTypes #-}
 {-# LANGUAGE BangPatterns #-}
 
-module Ply.Core.Typename (Typename, typeName) where
+module Ply.Core.Typename (Typename (Typename), typeName) where
 
 import Control.Monad (when)
 import Data.Aeson (FromJSON (parseJSON), ToJSON, Value (String))
diff --git a/ply-core/src/Ply/Core/Types.hs b/ply-core/src/Ply/Core/Types.hs
index 489b044..7110621 100644
--- a/ply-core/src/Ply/Core/Types.hs
+++ b/ply-core/src/Ply/Core/Types.hs
@@ -6,7 +6,7 @@ module Ply.Core.Types (
   ScriptRole (..),
   ScriptReaderException (..),
   TypedScriptEnvelope (..),
-  Typename,
+  Typename (Typename),
   UPLCProgram,
 ) where
 
@@ -36,7 +36,7 @@ import PlutusLedgerApi.Common (deserialiseUPLC, serialiseUPLC)
 import UntypedPlutusCore (DeBruijn, DefaultFun, DefaultUni, Program)
 
 import Ply.Core.Serialize.Script (serializeScriptCbor)
-import Ply.Core.Typename (Typename)
+import Ply.Core.Typename (Typename (Typename))
 
 type UPLCProgram = Program DeBruijn DefaultUni DefaultFun ()