diff --git a/aeson-via.cabal b/aeson-via.cabal
--- a/aeson-via.cabal
+++ b/aeson-via.cabal
@@ -1,13 +1,13 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.34.4.
+-- This file has been generated from package.yaml by hpack version 0.35.0.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 3ac16d6f86e6d171de5d3cc72a8987ac505fcf1735f4c3b83c7d7de664507281
+-- hash: d810620276cd1066523e2e1543d06ac95aafc53f99394226b2768f5a025d3346
 
 name:           aeson-via
-version:        0.2.0
+version:        0.2.1
 synopsis:       Wrappers to derive-via Aeson ToJSON/FromJSON typeclasses
 description:    Please see the README on GitHub at <https://github.com/ejconlon/aeson-via#readme>
 category:       Data
@@ -35,11 +35,11 @@
       src
   ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wpartial-fields -Wredundant-constraints -fno-warn-unused-top-binds
   build-depends:
-      aeson ==2.0.*
+      aeson >=2.0 && <2.2
     , aeson-casing ==0.2.*
     , base >=4.12 && <5
     , newtype-generics >=0.5 && <0.7
-    , text ==1.2.*
+    , text >=1.2 && <2.0
   default-language: Haskell2010
 
 test-suite aeson-via-test
@@ -51,12 +51,12 @@
       test
   ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wpartial-fields -Wredundant-constraints -fno-warn-unused-top-binds -threaded -rtsopts -with-rtsopts=-N
   build-depends:
-      aeson ==2.0.*
+      aeson >=2.0 && <2.2
     , aeson-casing ==0.2.*
     , aeson-via
     , base >=4.12 && <5
     , newtype-generics >=0.5 && <0.7
     , tasty >=1.2 && <1.5
     , tasty-hunit ==0.10.*
-    , text ==1.2.*
+    , text >=1.2 && <2.0
   default-language: Haskell2010
diff --git a/src/AesonVia.hs b/src/AesonVia.hs
--- a/src/AesonVia.hs
+++ b/src/AesonVia.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE UndecidableInstances #-}