diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Revision history for deriving-aeson
 
+## 0.2.8
+
+* Supported GHC 9.2
+* Supported aeson-2.0
+
 ## 0.2.7
 
 * Added a `StringModifier` instance to a list of types
diff --git a/deriving-aeson.cabal b/deriving-aeson.cabal
--- a/deriving-aeson.cabal
+++ b/deriving-aeson.cabal
@@ -1,6 +1,6 @@
 cabal-version:       2.4
 name:                deriving-aeson
-version:             0.2.7
+version:             0.2.8
 synopsis:            Type driven generic aeson instance customisation
 description:         This package provides a newtype wrapper with
   FromJSON/ToJSON instances customisable via a phantom type parameter.
@@ -13,7 +13,7 @@
 copyright:           Copyright (c) 2020 Fumiaki Kinoshita
 category:            JSON, Generics
 extra-source-files:  CHANGELOG.md, README.md
-tested-with:         GHC == 8.6.5, GHC == 8.8.3, GHC == 8.10.1
+tested-with:         GHC == 8.6.5, GHC == 8.8.3, GHC == 8.10.4, GHC == 9.2.1
 
 source-repository head
   type: git
@@ -23,7 +23,7 @@
   exposed-modules:
     Deriving.Aeson
     Deriving.Aeson.Stock
-  build-depends:       base >= 4.12 && <5, aeson >= 1.4.7.0 && <1.6
+  build-depends:       base >= 4.12 && <5, aeson >= 1.4.7.0 && <2.1
   hs-source-dirs: src
   default-language:    Haskell2010
   ghc-options: -Wall -Wcompat
diff --git a/src/Deriving/Aeson.hs b/src/Deriving/Aeson.hs
--- a/src/Deriving/Aeson.hs
+++ b/src/Deriving/Aeson.hs
@@ -128,7 +128,9 @@
 instance (KnownSymbol separator, NonEmptyString separator) => StringModifier (CamelTo separator) where
   getStringModifier = camelTo2 char
     where
-      (char : _) = symbolVal (Proxy @separator)
+      char = case symbolVal (Proxy @separator) of
+        c : _ -> c
+        _ -> error "Impossible"
 
 instance (KnownSymbol from, KnownSymbol to) => StringModifier (Rename from to) where
   getStringModifier s = if s == symbolVal (Proxy @from) then symbolVal (Proxy @to) else s
diff --git a/src/Deriving/Aeson/Stock.hs b/src/Deriving/Aeson/Stock.hs
--- a/src/Deriving/Aeson/Stock.hs
+++ b/src/Deriving/Aeson/Stock.hs
@@ -12,6 +12,7 @@
   , ToJSON
   , Generic) where
 
+import Data.Kind (Type)
 import Deriving.Aeson
 
 -- | Field names are prefixed by @str@; strip them from JSON representation
@@ -24,4 +25,4 @@
 type Snake = CustomJSON '[FieldLabelModifier CamelToSnake]
 
 -- | No customisation
-type Vanilla = CustomJSON '[]
+type Vanilla = CustomJSON ('[] :: [Type])