diff --git a/Data/Aeson/Types/FromJSON.hs b/Data/Aeson/Types/FromJSON.hs
--- a/Data/Aeson/Types/FromJSON.hs
+++ b/Data/Aeson/Types/FromJSON.hs
@@ -2130,11 +2130,11 @@
 
 parseQuarterOfYear :: T.Text -> Parser QuarterOfYear
 parseQuarterOfYear t = case T.toLower t of
-    "q1"  -> return Q1
-    "q2"  -> return Q2
-    "q3"  -> return Q3
-    "e4 " -> return Q4
-    _     -> fail "Ivalid quarter of year"
+    "q1" -> return Q1
+    "q2" -> return Q2
+    "q3" -> return Q3
+    "q4" -> return Q4
+    _    -> fail "Invalid quarter of year"
 
 instance FromJSONKey QuarterOfYear where
     fromJSONKey = FromJSONKeyTextParser parseQuarterOfYear
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2011, MailRank, Inc. 2014-2020 Aeson project contributors
+Copyright (c) 2011, MailRank, Inc. 2014-2021 Aeson project contributors
 
 All rights reserved.
 
diff --git a/aeson.cabal b/aeson.cabal
--- a/aeson.cabal
+++ b/aeson.cabal
@@ -1,5 +1,5 @@
 name:            aeson
-version:         1.5.5.0
+version:         1.5.5.1
 license:         BSD3
 license-file:    LICENSE
 category:        Text, Web, JSON
@@ -235,7 +235,7 @@
     unordered-containers,
     uuid-types,
     vector,
-    quickcheck-instances >= 0.3.24 && <0.4
+    quickcheck-instances >= 0.3.25.2 && <0.4
 
   if flag(bytestring-builder)
     build-depends: bytestring >= 0.9 && < 0.10.4,
diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,8 @@
 For the latest version of this document, please see [https://github.com/bos/aeson/blob/master/changelog.md](https://github.com/bos/aeson/blob/master/changelog.md).
 
+### 1.5.5.1
+* Fix a bug in `FromJSON QuarterOfYear` instance.
+
 ### 1.5.5.0
 * Add instances for `Month`, `Quarter` and `QuarterOfYear` (from `time-1.11`), thanks to Oleg Grenrus.
 
diff --git a/stack.yaml b/stack.yaml
new file mode 100644
--- /dev/null
+++ b/stack.yaml
@@ -0,0 +1,15 @@
+resolver: lts-12.26
+packages:
+- '.'
+- attoparsec-iso8601
+flags:
+  aeson:
+    fast: true
+    cffi: true
+extra-deps:
+- base-orphans-0.8.1
+- hashable-time-0.2.0.1
+- QuickCheck-2.13.1
+- quickcheck-instances-0.3.21
+- splitmix-0.0.2
+- time-compat-1.9.2.2