diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+1.2.9
+
+* [Build against `aeson-2.0`](https://github.com/dhall-lang/dhall-haskell/pull/2315)
+
 1.2.8
 
 * Build against `dhall-1.40.0`
diff --git a/dhall-yaml.cabal b/dhall-yaml.cabal
--- a/dhall-yaml.cabal
+++ b/dhall-yaml.cabal
@@ -1,5 +1,5 @@
 Name: dhall-yaml
-Version: 1.2.8
+Version: 1.2.9
 Cabal-Version: >=1.10
 Build-Type: Simple
 License: GPL-3
@@ -34,7 +34,7 @@
         HsYAML                    >= 0.2       && < 0.3 ,
         HsYAML-aeson              >= 0.2       && < 0.3 ,
         base                      >= 4.11.0.0  && < 5   ,
-        aeson                     >= 1.0.0.0   && < 1.6 ,
+        aeson                     >= 1.0.0.0   && < 2.1 ,
         bytestring                                < 0.12,
         dhall                     >= 1.31.0    && < 1.41,
         dhall-json                >= 1.6.0     && < 1.8 ,
@@ -72,7 +72,7 @@
         dhall-yaml                                       ,
         exceptions                  >= 0.8.3    && < 0.11,
         optparse-applicative                             ,
-        prettyprinter                                    ,
+        prettyprinter               >= 1.7.0             ,
         prettyprinter-ansi-terminal >= 1.1.1    && < 1.2 ,
         text                                       < 1.3
     Other-Modules:
diff --git a/yaml-to-dhall/Main.hs b/yaml-to-dhall/Main.hs
--- a/yaml-to-dhall/Main.hs
+++ b/yaml-to-dhall/Main.hs
@@ -16,14 +16,14 @@
 import Options.Applicative (Parser, ParserInfo)
 
 import qualified Control.Exception
-import qualified Data.ByteString.Char8                     as BSL8
-import qualified Dhall.YamlToDhall                         as YamlToDhall
+import qualified Data.ByteString.Char8 as BSL8
 import qualified Dhall.Util
+import qualified Dhall.YamlToDhall     as YamlToDhall
 import qualified GHC.IO.Encoding
-import qualified Options.Applicative                       as Options
-import qualified Paths_dhall_yaml                          as Meta
+import qualified Options.Applicative   as Options
+import qualified Paths_dhall_yaml      as Meta
 import qualified System.Exit
-import qualified System.IO                                 as IO
+import qualified System.IO             as IO
 
 -- ---------------
 -- Command options