diff --git a/Data/Git/Monad.hs b/Data/Git/Monad.hs
index 480af9f33b35795f9ca50b66d59ad446fab9ceeb..b3369d291f1193e0eb44e855743932a4ca272b4d 100644
--- a/Data/Git/Monad.hs
+++ b/Data/Git/Monad.hs
@@ -127,7 +127,7 @@ instance Resolvable Git.RefName where
 
 -- | Basic operations common between the different Monads defined in this
 -- package.
-class (Functor m, Applicative m, Monad m) => GitMonad m where
+class (Functor m, Applicative m, Monad m, MonadFail m) => GitMonad m where
     -- | the current Monad must allow access to the current Git
     getGit :: m (Git.Git SHA1)
     liftGit :: IO a -> m a
@@ -240,6 +240,8 @@ instance Applicative GitM where
 instance Monad GitM where
     return = returnGitM
     (>>=)  = bindGitM
+
+instance MonadFail GitM where
     fail   = failGitM
 
 instance GitMonad GitM where
@@ -313,6 +315,8 @@ instance Applicative CommitAccessM where
 instance Monad CommitAccessM where
     return = returnCommitAccessM
     (>>=)  = bindCommitAccessM
+
+instance MonadFail CommitAccessM where
     fail   = failCommitAccessM
 
 instance GitMonad CommitAccessM where
@@ -474,6 +478,8 @@ instance Applicative CommitM where
 instance Monad CommitM where
     return = returnCommitM
     (>>=)  = bindCommitM
+
+instance MonadFail CommitM where
     fail   = failCommitM
 
 instance GitMonad CommitM where
diff --git a/git.cabal b/git.cabal
index 1d5748efce2d5245be5890758a99fc1b182f04d3..72e69359cbc4e35d1ccf773dec6097bc65116215 100644
--- a/git.cabal
+++ b/git.cabal
@@ -26,7 +26,7 @@ data-files:          README.md
 extra-source-files:  tests/*.hs
 
 Library
-  Build-Depends:     base >= 4 && < 5
+  Build-Depends:     base >= 4.13 && < 5
                    , basement
                    , bytestring >= 0.9
                    , containers
diff --git a/stack.yaml b/stack.yaml
index 34c4074597ac429d90a555f8e02678ddce036988..bed42e7433c17f1d9758c7f33e4e03159d8b05fb 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,3 +1,8 @@
-# ~*~ auto-generated by haskell-ci with config : 0a4c6a0fd68c5b852764201c037cae7f29b1cb3f3856f78d1a20fe2e44845097 ~*~
-{ resolver: lts-13.5, packages: [ '.' ], extra-deps: [], flags: {} }
+resolver: nightly-2020-12-12
 
+packages:
+  - '.'
+
+extra-deps: []
+
+flags: {}
diff --git a/stack.yaml.lock b/stack.yaml.lock
new file mode 100644
index 0000000000000000000000000000000000000000..aa36300665c9411e6631bf540375dfae0d9b8047
--- /dev/null
+++ b/stack.yaml.lock
@@ -0,0 +1,12 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages: []
+snapshots:
+- completed:
+    size: 556770
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/nightly/2020/12/12.yaml
+    sha256: 168062744e171ba6949149ee702483d2186ddfbb6038508576d6c5093245f534
+  original: nightly-2020-12-12