diff --git a/CHANGES.md b/CHANGES.md
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,6 +1,11 @@
 Release notes for glambda
 =========================
 
+1.0.1
+-----
+
+Update package dependencies to drop dependency on `errors`.
+
 1.0
 ---
 
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -100,12 +100,12 @@
 Good-bye.
 ~~~
 
-As you can see, glambda uses [de Bruijn indices][1] to track variable binding.
+As you can see, glambda uses [de Bruijn indices][3] to track variable binding.
 In the actual output (if your console supports it), the binders (`#`) and
 usage sites (`#0`, `#1`) are colored so that humans can easily tell which
 variable is used where.
 
-[1]: https://en.wikipedia.org/wiki/De_Bruijn_index
+[3]: https://en.wikipedia.org/wiki/De_Bruijn_index
 
 You can also see above that the input to glambda must be fully annotated;
 glambda does *not* do type inference. However, note that types on binders
diff --git a/glambda.cabal b/glambda.cabal
--- a/glambda.cabal
+++ b/glambda.cabal
@@ -1,5 +1,5 @@
 name:           glambda
-version:        1.0
+version:        1.0.1
 cabal-version:  >= 1.10
 synopsis:       A simply typed lambda calculus interpreter, written with GADTs
 homepage:       https://github.com/goldfirere/glambda
@@ -22,12 +22,13 @@
 source-repository this
   type:     git
   location: https://github.com/goldfirere/glambda.git
-  tag:      v1.0
+  tag:      v1.0.1
 
 library
   build-depends:      base == 4.*
                     , ansi-wl-pprint >= 0.6.7.1
-                    , errors >= 1.4.6 && < 2.0
+                    , transformers >= 0.3.0.0
+                    , either >= 4.0
                     , mtl >= 2.1.3.1
                     , containers >= 0.5
                     , parsec >= 3.1
@@ -80,7 +81,7 @@
                     , glambda
                     , template-haskell
                     , ansi-wl-pprint >= 0.6.7.1
-                    , errors >= 1.4.6 && < 2.0
+                    , either >= 4.0
                     , mtl >= 2.1.3.1
                     , parsec >= 3.1
                     , tasty >= 0.8.1
diff --git a/src/Language/Glambda/Monad.hs b/src/Language/Glambda/Monad.hs
--- a/src/Language/Glambda/Monad.hs
+++ b/src/Language/Glambda/Monad.hs
@@ -33,7 +33,8 @@
 
 import Text.PrettyPrint.ANSI.Leijen
 
-import Control.Error
+import Control.Monad.Trans.Maybe
+import Control.Monad.Trans.Either
 import Control.Monad.Reader
 import Control.Monad.Error
 import Control.Monad.State
diff --git a/tests/Tests/Check.hs b/tests/Tests/Check.hs
--- a/tests/Tests/Check.hs
+++ b/tests/Tests/Check.hs
@@ -13,11 +13,12 @@
 import Language.Glambda.Globals
 import Language.Glambda.Util
 
-import Control.Error
+import Control.Monad.Trans.Either
 import Control.Monad.Reader
 
 import Text.PrettyPrint.ANSI.Leijen
 
+import Data.Maybe
 import Data.List as List
 import Control.Arrow as Arrow