diff --git a/shelly.cabal b/shelly.cabal
--- a/shelly.cabal
+++ b/shelly.cabal
@@ -1,6 +1,6 @@
 Name:       shelly
 
-Version:     0.15.4
+Version:     0.15.4.1
 Synopsis:    shell-like (systems) programming in Haskell
 
 Description: Shelly provides convenient systems programming in Haskell,
@@ -37,7 +37,7 @@
   other-modules:   Shelly.Base, Shelly.Find
 
   Build-depends: base >= 4 && < 5, containers
-               , time, directory, text, mtl
+               , time, directory, text, mtl >= 2
                , process >= 1.0
                , unix-compat < 0.5
                , system-filepath >= 0.4.7 && < 0.5