diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,17 @@
 # pinpon changelog
 
+## 0.2.0.2
+
+Fixes:
+
+  - Fix hlint 2.1 issue.
+
+  - Fix a bounds typo in package.yaml.
+
+Changes:
+
+  - Bump hlint upper bound.
+
 ## 0.2.0.1
 
 Changes:
diff --git a/package.yaml b/package.yaml
--- a/package.yaml
+++ b/package.yaml
@@ -1,5 +1,5 @@
 name:       pinpon
-version:    0.2.0.1
+version:    0.2.0.2
 synopsis:   A gateway for various cloud notification services
 category:   Network
 stability:  experimental
@@ -116,7 +116,7 @@
   - http-types          >=0.9.1  && <0.10
   - lens                ==4.15.*
   - lucid               >=2.9.9  && <3
-  - mtl                 ==2.2.1  && <2.3
+  - mtl                 >=2.2.1  && <2.3
   - protolude           ==0.2.*
   - resourcet           >=1.1.9  && <1.2
   - servant             ==0.11.*
@@ -240,7 +240,7 @@
       else:
         dependencies:
         - base
-        - hlint     ==2.0.*
+        - hlint     >=2.0 && <2.2
         - protolude
   doctest:
     <<: *test
diff --git a/pinpon.cabal b/pinpon.cabal
--- a/pinpon.cabal
+++ b/pinpon.cabal
@@ -1,11 +1,11 @@
--- This file has been generated from package.yaml by hpack version 0.21.2.
+-- This file has been generated from package.yaml by hpack version 0.27.0.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: ed2620ae2820a31b4c16cfcc7335a51248afdd96daffda59da6dee3be41fb25a
+-- hash: ae6d5ceb311afb4ad42b828e2776e55db2c1a23aaa3d83a1c1be1f795294d7e7
 
 name:                   pinpon
-version:                0.2.0.1
+version:                0.2.0.2
 synopsis:               A gateway for various cloud notification services
 description:            @pinpon@ is a gateway for various cloud notification services, such
                         as the Amazon AWS SNS service.
@@ -120,7 +120,7 @@
     , http-types >=0.9.1 && <0.10
     , lens ==4.15.*
     , lucid >=2.9.9 && <3
-    , mtl ==2.2.1 && <2.3
+    , mtl >=2.2.1 && <2.3
     , protolude ==0.2.*
     , resourcet >=1.1.9 && <1.2
     , servant ==0.11.*
@@ -262,7 +262,7 @@
   else
     build-depends:
         base
-      , hlint ==2.0.*
+      , hlint >=2.0 && <2.2
       , protolude
   default-language: Haskell2010
 
@@ -289,6 +289,6 @@
   else
     build-depends:
         base
-      , hlint ==2.0.*
+      , hlint >=2.0 && <2.2
       , protolude
   default-language: Haskell2010
diff --git a/src/Network/PinPon/AWS.hs b/src/Network/PinPon/AWS.hs
--- a/src/Network/PinPon/AWS.hs
+++ b/src/Network/PinPon/AWS.hs
@@ -34,5 +34,5 @@
 
 errMsg :: Error -> BL.ByteString
 errMsg (ServiceError e) = maybe "Unspecified error" (toSL . toText) $ e ^. serviceMessage
-errMsg (SerializeError e) = e ^. serializeMessage ^. packedChars
+errMsg (SerializeError e) = e ^. (serializeMessage . packedChars)
 errMsg (TransportError e) = show e ^. packedChars