diff --git a/aeson-gadt-th.cabal b/aeson-gadt-th.cabal
--- a/aeson-gadt-th.cabal
+++ b/aeson-gadt-th.cabal
@@ -1,6 +1,6 @@
-cabal-version: >=1.10
+cabal-version: >=2.0
 name: aeson-gadt-th
-version: 0.1.2.0
+version: 0.1.2.1
 synopsis: Derivation of Aeson instances for GADTs
 category: JSON
 description: Template Haskell for generating ToJSON and FromJSON instances for GADTs. See <https://github.com/obsidiansystems/aeson-gadt-th/blob/master/README.md README.md> for examples.
@@ -27,10 +27,10 @@
                , aeson
                , dependent-sum
                , aeson-gadt-th
-               , markdown-unlit
   default-language: Haskell2010
   main-is: README.lhs
   ghc-options: -pgmL markdown-unlit -Wall
+  build-tool-depends: markdown-unlit:markdown-unlit
 
 source-repository head
   type:     git