diff --git a/hsemail.cabal b/hsemail.cabal
--- a/hsemail.cabal
+++ b/hsemail.cabal
@@ -1,5 +1,5 @@
 name:               hsemail
-version:            2.2.0
+version:            2.2.1
 synopsis:           Parsec parsers for the Internet Message format (e-mail)
 description:        Parsec parsers for the Internet Message format defined in RFC2822.
 license:            BSD3
@@ -10,7 +10,7 @@
                     Marty Pauley
 maintainer:         Peter Simons <simons@cryp.to>
 stability:          stable
-tested-with:        GHC == 7.10.3, GHC == 8.0.2, GHC == 8.2.2, GHC == 8.4.4, GHC == 8.6.5
+tested-with:        GHC == 7.10.3 || == 8.0.2 || == 8.2.2 || == 8.4.4 || == 8.6.5 || == 8.8.4 || == 8.10.2
 category:           Parsing
 homepage:           https://github.com/peti/hsemail#readme
 bug-reports:        https://github.com/peti/hsemail/issues
diff --git a/src/Text/Parsec/Rfc2822.hs b/src/Text/Parsec/Rfc2822.hs
--- a/src/Text/Parsec/Rfc2822.hs
+++ b/src/Text/Parsec/Rfc2822.hs
@@ -309,7 +309,7 @@
 
 day_of_month :: Stream s m Char => ParsecT s u m Int
 day_of_month = do r <- fmap read (manyNtoM 1 2 digit)
-                  guard (r >= 1 && r < 31)
+                  guard (r >= 1 && r <= 31)
                   return r
 
 -- | Match a 1 or 2-digit number (day of month), recognizing both standard and
diff --git a/test/spec.hs b/test/spec.hs
--- a/test/spec.hs
+++ b/test/spec.hs
@@ -35,12 +35,14 @@
 
   describe "Rfc2822.day" $ do
     it "parses a hand-picked day-of-months correctly" $ do
+      parseTest day "1" `shouldReturn` 1
       parseTest day "09" `shouldReturn` 9
       parseTest day "15" `shouldReturn` 15
+      parseTest day "31" `shouldReturn` 31
 
     it "does perform range checking" $ do
       parseFailure day "00"
-      parseFailure day "99"
+      parseFailure day "32"
 
     it "fails properly on incomplete input" $ do
       parseFailure day "Mon"