diff --git a/Control/Monad/Logic.hs b/Control/Monad/Logic.hs
--- a/Control/Monad/Logic.hs
+++ b/Control/Monad/Logic.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE UndecidableInstances, Rank2Types, FlexibleInstances, MultiParamTypeClasses #-}
+{-# LANGUAGE CPP, UndecidableInstances, Rank2Types, FlexibleInstances, MultiParamTypeClasses #-}
 
 -------------------------------------------------------------------------
 -- |
@@ -41,6 +41,7 @@
 import Control.Applicative
 
 import Control.Monad
+import qualified Control.Monad.Fail as Fail
 import Control.Monad.Identity
 import Control.Monad.Trans
 
@@ -63,7 +64,11 @@
 -------------------------------------------------------------------------
 -- | Extracts the first result from a LogicT computation,
 -- failing otherwise.
+#if !MIN_VERSION_base(4,13,0)
 observeT :: Monad m => LogicT m a -> m a
+#else
+observeT :: MonadFail m => LogicT m a -> m a
+#endif
 observeT lt = unLogicT lt (const . return) (fail "No answer.")
 
 -------------------------------------------------------------------------
@@ -103,7 +108,7 @@
 -------------------------------------------------------------------------
 -- | Extracts the first result from a Logic computation.
 observe :: Logic a -> a
-observe = runIdentity . observeT 
+observe lt = runIdentity $ unLogicT lt (const . return) (error "No answer.")
 
 -------------------------------------------------------------------------
 -- | Extracts all results from a Logic computation.
@@ -138,6 +143,11 @@
 instance Monad (LogicT m) where
     return a = LogicT $ \sk fk -> sk a fk
     m >>= f = LogicT $ \sk fk -> unLogicT m (\a fk' -> unLogicT (f a) sk fk') fk
+#if !MIN_VERSION_base(4,13,0)
+    fail = Fail.fail
+#endif
+
+instance Fail.MonadFail (LogicT m) where
     fail _ = LogicT $ \_ fk -> fk
 
 instance MonadPlus (LogicT m) where
diff --git a/changelog.md b/changelog.md
new file mode 100644
--- /dev/null
+++ b/changelog.md
@@ -0,0 +1,3 @@
+# 0.6.0.3
+
+* Comply with MonadFail proposal.
diff --git a/logict.cabal b/logict.cabal
--- a/logict.cabal
+++ b/logict.cabal
@@ -1,5 +1,5 @@
 name:                   logict
-version:                0.6.0.2
+version:                0.6.0.3
 description:            A continuation-based, backtracking, logic programming monad.
                         An adaptation of the two-continuation implementation found
                         in the paper "Backtracking, Interleaving, and Terminating
@@ -13,18 +13,21 @@
                         Copyright (c) 2011-2013, Edward Kmett,
                         Copyright (c) 2014, Roman Cheplyaka
 author:                 Dan Doel
-maintainer:             dan.doel@gmail.com
-homepage:               http://code.haskell.org/~dolio/
+maintainer:             Andrew Lelechenko <andrew.lelechenko@gmail.com>
+homepage:               https://github.com/Bodigrim/logict#readme
 cabal-version:          >= 1.9.2
 tested-with:            GHC
 build-type:             Simple
+extra-source-files:     changelog.md
 
 source-repository head
-  type:     darcs
-  location: http://hub.darcs.net/dolio/logict
+  type: git
+  location: https://github.com/Bodigrim/logict
 
 library
   build-depends:          base >=2 && < 5, mtl>=2 && <2.3
+  if impl(ghc < 8.0)
+    build-depends:        fail
 
   exposed-modules:        Control.Monad.Logic,
                           Control.Monad.Logic.Class