diff --git a/CHANGELOG.md b/CHANGELOG.md
index 69663e9..ff33b3c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,11 @@ The format is based on
 and this project adheres to
 [Haskell Package Versioning Policy](https://pvp.haskell.org/).
 
+## [Unreleased]
+### Changed
+- Removed deprecated `Language.GraphQL.Error` functions: `addErr`, `addErrMsg`,
+  `singleError`.
+
 ## [1.0.3.0] - 2022-03-27
 ### Fixed
 - Index position in error path. (Index and Segment paths of a field have been
@@ -477,6 +482,7 @@ and this project adheres to
 ### Added
 - Data types for the GraphQL language.
 
+[Unreleased]: https://www.caraus.tech/projects/pub-graphql/repository/23/diff?rev=master&rev_to=v1.0.3.0
 [1.0.3.0]: https://www.caraus.tech/projects/pub-graphql/repository/23/diff?rev=1.0.3.0&rev_to=v1.0.2.0
 [1.0.2.0]: https://www.caraus.tech/projects/pub-graphql/repository/23/diff?rev=1.0.2.0&rev_to=v1.0.1.0
 [1.0.1.0]: https://www.caraus.tech/projects/pub-graphql/repository/23/diff?rev=v1.0.1.0&rev_to=v1.0.0.0
diff --git a/graphql.cabal b/graphql.cabal
index c50029e..073b4db 100644
--- a/graphql.cabal
+++ b/graphql.cabal
@@ -11,7 +11,7 @@ author:         Danny Navarro <j@dannynavarro.net>,
                 Matthías Páll Gissurarson <mpg@mpg.is>,
                 Sólrún Halla Einarsdóttir <she@mpg.is>
 maintainer:     belka@caraus.de
-copyright:      (c) 2019-2021 Eugen Wissner,
+copyright:      (c) 2019-2022 Eugen Wissner,
                 (c) 2015-2017 J. Daniel Navarro
 license:        MPL-2.0 AND BSD-3-Clause
 license-files:  LICENSE,
diff --git a/src/Language/GraphQL/Error.hs b/src/Language/GraphQL/Error.hs
index 4e461f0..ffd3a78 100644
--- a/src/Language/GraphQL/Error.hs
+++ b/src/Language/GraphQL/Error.hs
@@ -15,16 +15,13 @@ module Language.GraphQL.Error
     , ResolverException(..)
     , Response(..)
     , ResponseEventStream
-    , addErr
-    , addErrMsg
     , parseError
     , runCollectErrs
-    , singleError
     ) where
 
 import Conduit
 import Control.Exception (Exception(..))
-import Control.Monad.Trans.State (StateT, modify, runStateT)
+import Control.Monad.Trans.State (StateT, runStateT)
 import Data.HashMap.Strict (HashMap)
 import Data.Sequence (Seq(..), (|>))
 import qualified Data.Sequence as Seq
@@ -131,26 +128,3 @@ data Resolution m = Resolution
 -- /CollectErrsT was part of the old executor and isn't used anymore, it will be
 -- deprecated in the future and removed./
 type CollectErrsT m = StateT (Resolution m) m
-
--- | Adds an error to the list of errors.
-{-# DEPRECATED #-}
-addErr :: Monad m => Error -> CollectErrsT m ()
-addErr v = modify appender
-  where
-    appender :: Monad m => Resolution m -> Resolution m
-    appender resolution@Resolution{..} = resolution{ errors = errors |> v }
-
-{-# DEPRECATED #-}
-makeErrorMessage :: Text -> Error
-makeErrorMessage s = Error s [] []
-
--- | Constructs a response object containing only the error with the given
--- message.
-{-# DEPRECATED #-}
-singleError :: Serialize a => Text -> Response a
-singleError message = Response null $ Seq.singleton $ Error message [] []
-
--- | Convenience function for just wrapping an error message.
-{-# DEPRECATED #-}
-addErrMsg :: (Monad m, Serialize a) => Text -> CollectErrsT m a
-addErrMsg errorMessage = (addErr . makeErrorMessage) errorMessage >> pure null