diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,33 @@
 # Changelog
 
+## 5.0.0 (2021-04-14)
+
+This release brings `versions` in line with version `2.0.0` of the SemVer spec.
+The main addition to the spec is the allowance of hyphens in both the prerelease
+and metadata sections. As such, **certain versions like `1.2.3+1-1` which
+previously would not parse as SemVer now do.**
+
+To accomodate this and other small spec updates, the `SemVer` and `Version`
+types have received breaking changes here.
+
+#### Changed
+
+- **Breaking:** The `_svMeta` field of `SemVer` is now parsed as a dumber `Maybe
+  Text` instead of `[VChunk]`, due to metadata now being allowed to possess
+  leading zeroes.
+- **Breaking:** Like the above, the `_vMeta` field of `Version` is now `Maybe Text`.
+- **Breaking: The `_vRel` and `_vMeta` fields of `Version` have had their order
+  flipped.** Further, the prelease and meta sections are now expected in the
+  same order as `SemVer` when parsing (prerel first, meta second). `Version` is
+  thus now a quite similar to `SemVer`, except allowing letters in more
+  permissive positions.
+- **Breaking:** The `meta` traversal has been altered to accomodate the metadata
+  field changes.
+
+#### Fixed
+
+- Parsing certain legal SemVers specified in the spec.
+
 ## 4.0.3 (2021-02-23)
 
 #### Changed
diff --git a/Data/Versions.hs b/Data/Versions.hs
--- a/Data/Versions.hs
+++ b/Data/Versions.hs
@@ -7,7 +7,7 @@
 
 -- |
 -- Module    : Data.Versions
--- Copyright : (c) Colin Woodbury, 2015 - 2020
+-- Copyright : (c) Colin Woodbury, 2015 - 2021
 -- License   : BSD3
 -- Maintainer: Colin Woodbury <colin@fosskers.ca>
 --
@@ -29,6 +29,8 @@
 -- currently using it. It provides consistency in version incrementing and has
 -- the best constraints on comparisons.
 --
+-- __This library implements version @2.0.0@ of the SemVer spec.__
+--
 -- == Using the Parsers
 -- In general, `versioning` is the function you want. It attempts to parse a
 -- given `Text` using the three individual parsers, `semver`, `version` and
@@ -74,7 +76,7 @@
 import           Control.DeepSeq
 import           Control.Monad (void)
 import           Data.Bool (bool)
-import           Data.Char (isAlpha)
+import           Data.Char (isAlpha, isAlphaNum)
 import           Data.Foldable (fold)
 import           Data.Hashable (Hashable)
 import           Data.List (intersperse)
@@ -140,19 +142,23 @@
 -- | Convert a `SemVer` to a `Version`.
 vFromS :: SemVer -> Version
 vFromS (SemVer ma mi pa re me) =
-  Version Nothing ((Digits ma :| []) :| [(Digits mi :| []), Digits pa :| []]) re me
+  Version
+  { _vEpoch = Nothing
+  , _vChunks = (Digits ma :| []) :| [Digits mi :| [], Digits pa :| []]
+  , _vMeta = me
+  , _vRel = re }
 
 -- | Convert a `Version` to a `Mess`.
 mFromV :: Version -> Mess
-mFromV (Version e v m r) = maybe affix (\a -> Mess (MDigit a (showt a) :| []) $ Just (VColon, affix)) e
+mFromV (Version e v r m) = maybe affix (\a -> Mess (MDigit a (showt a) :| []) $ Just (VColon, affix)) e
   where
     affix :: Mess
     affix = Mess (chunksAsM v) m'
 
     m' :: Maybe (VSep, Mess)
-    m' = case NEL.nonEmpty m of
+    m' = case m of
       Nothing  -> r'
-      Just m'' -> Just (VPlus, Mess (chunksAsM m'') r')
+      Just m'' -> Just (VPlus, Mess (MPlain m'' :| []) r')
 
     r' :: Maybe (VSep, Mess)
     r' = case NEL.nonEmpty r of
@@ -246,16 +252,19 @@
 _Mess f t = either (const (pure t)) (fmap prettyMess . f) $ mess t
 {-# INLINE _Mess #-}
 
+-- | Possibly extract a `SemVer` from a `Versioning`.
 _Ideal :: Traversal' Versioning SemVer
 _Ideal f (Ideal s) = Ideal <$> f s
 _Ideal _ v         = pure v
 {-# INLINE _Ideal #-}
 
+-- | Possibly extract a `Version` from a `Versioning`.
 _General :: Traversal' Versioning Version
 _General f (General v) = General <$> f v
 _General _ v           = pure v
 {-# INLINE _General #-}
 
+-- | Possibly extract a `Mess` from a `Versioning`.
 _Complex :: Traversal' Versioning Mess
 _Complex f (Complex m) = Complex <$> f m
 _Complex _ v           = pure v
@@ -303,7 +312,7 @@
   -- | @major.minor.patch-PREREL+meta@
   release  :: Traversal' v [VChunk]
   -- | @major.minor.patch-prerel+META@
-  meta     :: Traversal' v [VChunk]
+  meta     :: Traversal' v (Maybe Text)
   -- | A Natural Transformation into an proper `SemVer`.
   semantic :: Traversal' v SemVer
 
@@ -331,7 +340,7 @@
 --
 -- 2. Build metadata does not affect version precedence.
 --
--- 3. PREREL and META strings may only contain ASCII alphanumerics.
+-- 3. PREREL and META strings may only contain ASCII alphanumerics and hyphens.
 --
 -- For more information, see http://semver.org
 data SemVer = SemVer
@@ -339,7 +348,7 @@
   , _svMinor  :: !Word
   , _svPatch  :: !Word
   , _svPreRel :: ![VChunk]
-  , _svMeta   :: ![VChunk] }
+  , _svMeta   :: !(Maybe Text) }
   deriving stock (Show, Generic)
   deriving anyclass (NFData, Hashable)
 
@@ -362,10 +371,10 @@
 
 instance Semigroup SemVer where
   SemVer mj mn pa p m <> SemVer mj' mn' pa' p' m' =
-    SemVer (mj + mj') (mn + mn') (pa + pa') (p ++ p') (m ++ m')
+    SemVer (mj + mj') (mn + mn') (pa + pa') (p ++ p') (m <> m')
 
 instance Monoid SemVer where
-  mempty = SemVer 0 0 0 [] []
+  mempty = SemVer 0 0 0 [] Nothing
 
 #if !MIN_VERSION_base(4,11,0)
   mappend = (<>)
@@ -418,11 +427,13 @@
 str :: Text -> Maybe VUnit
 str t = bool Nothing (Just $ Str t) $ T.all isAlpha t
 
+-- | Possibly traverse the inner digit value of a `VUnit`.
 _Digits :: Traversal' VUnit Word
 _Digits f (Digits i) = Digits <$> f i
 _Digits _ v          = pure v
 {-# INLINE _Digits #-}
 
+-- | Possibly traverse the inner text of a `VUnit`.
 _Str :: Traversal' VUnit Text
 _Str f (Str t) = Str . (\t' -> bool t t' (T.all isAlpha t')) <$> f t
 _Str _ v       = pure v
@@ -479,22 +490,22 @@
   {-# INLINE minor #-}
 
   patch f (PVP (m :| mi : pa : rs)) = (\pa' -> PVP $ m :| mi : pa' : rs) <$> f pa
-  patch f (PVP (m :| mi : []))      = (\pa' -> PVP $ m :| mi : [pa']) <$> f 0
+  patch f (PVP (m :| [mi]))         = (\pa' -> PVP $ m :| mi : [pa']) <$> f 0
   patch f (PVP (m :| []))           = (\pa' -> PVP $ m :| 0 : [pa']) <$> f 0
   {-# INLINE patch #-}
 
-  release f p = const p <$> f []
+  release f p = p <$ f []
   {-# INLINE release #-}
 
-  meta f p = const p <$> f []
+  meta f p = p <$ f Nothing
   {-# INLINE meta #-}
 
   semantic f (PVP (m :| rs)) = (\(SemVer ma mi pa _ _) -> PVP $ ma :| [mi, pa]) <$> f s
     where
       s = case rs of
-        mi : pa : _ -> SemVer m mi pa [] []
-        mi : _      -> SemVer m mi 0  [] []
-        []          -> SemVer m 0 0   [] []
+        mi : pa : _ -> SemVer m mi pa [] Nothing
+        mi : _      -> SemVer m mi 0  [] Nothing
+        []          -> SemVer m 0 0   [] Nothing
   {-# INLINE semantic #-}
 
 --------------------------------------------------------------------------------
@@ -506,27 +517,28 @@
 --
 -- Generally conforms to the @a.b.c-p@ pattern, and may optionally have an
 -- /epoch/ and /metadata/. Epochs are prefixes marked by a colon, like in
--- @1:2.3.4@. Metadata is prefixed by @+@, and unlike SemVer can appear before
+-- @1:2.3.4@. Metadata is prefixed by @+@, and like SemVer must appear after
 -- the "prerelease" (the @-p@).
 --
 -- Examples of @Version@ that are not @SemVer@: 0.25-2, 8.u51-1, 20150826-1,
--- 1:2.3.4, 1.11.0+20200830-1
+-- 1:2.3.4
 data Version = Version
   { _vEpoch  :: !(Maybe Word)
   , _vChunks :: !(NonEmpty VChunk)
-  , _vMeta   :: ![VChunk]
-  , _vRel    :: ![VChunk] }
+  , _vRel    :: ![VChunk]
+  , _vMeta   :: !(Maybe Text) }
   deriving stock (Eq, Show, Generic)
   deriving anyclass (NFData, Hashable)
 
 instance Semigroup Version where
   Version e c m r <> Version e' c' m' r' = Version ((+) <$> e <*> e') (c <> c') (m <> m') (r <> r')
 
--- | Customized.
+-- | Customized. As in SemVer, metadata is ignored for the purpose of
+-- comparison.
 instance Ord Version where
   -- | For the purposes of Versions with epochs, `Nothing` is the same as `Just 0`,
   -- so we need to compare their actual version numbers.
-  compare (Version ae as _ rs) (Version be bs _ rs') = case compare (fromMaybe 0 ae) (fromMaybe 0 be) of
+  compare (Version ae as rs _) (Version be bs rs' _) = case compare (fromMaybe 0 ae) (fromMaybe 0 be) of
     EQ  -> case g (NEL.toList as) (NEL.toList bs) of
       -- If the two Versions were otherwise equal and recursed down this far,
       -- we need to compare them by their "release" values.
@@ -601,11 +613,12 @@
   meta _ v = pure v
   {-# INLINE meta #-}
 
-  semantic f (Version _ ((Digits a:|[]) :| (Digits b:|[]) : (Digits c:|[]) : _) me rs) =
-    vFromS <$> f (SemVer a b c me rs)
+  semantic f (Version _ ((Digits a:|[]) :| (Digits b:|[]) : (Digits c:|[]) : _) rs me) =
+    vFromS <$> f (SemVer a b c rs me)
   semantic _ v = pure v
   {-# INLINE semantic #-}
 
+-- | A `Version`'s inner epoch `Word`.
 epoch :: Lens' Version (Maybe Word)
 epoch f v = fmap (\ve -> v { _vEpoch = ve }) (f $ _vEpoch v)
 {-# INLINE epoch #-}
@@ -679,7 +692,7 @@
 --
 -- Example: @1.6.0a+2014+m872b87e73dfb-1@ We should be able to extract @0a@ safely.
 messPatchChunk :: Mess -> Maybe VChunk
-messPatchChunk (Mess (_ :| _ : MPlain p : _) _) = hush $ parse chunk "Chunk" p
+messPatchChunk (Mess (_ :| _ : MPlain p : _) _) = hush $ parse (chunkWith unit) "Chunk" p
 messPatchChunk _                                = Nothing
 
 instance Ord Mess where
@@ -715,7 +728,7 @@
 
   -- | Good luck.
   semantic f (Mess (MDigit t0 _ :| MDigit t1 _ : MDigit t2 _ : _) _) =
-    mFromV . vFromS <$> (f $ SemVer t0 t1 t2 [] [])
+    mFromV . vFromS <$> f (SemVer t0 t1 t2 [] Nothing)
   semantic _ v = pure v
   {-# INLINE semantic #-}
 
@@ -733,7 +746,7 @@
 --------------------------------------------------------------------------------
 -- Parsing
 
--- | A synonym for the more verbose `megaparsec` error type.
+-- | A synonym for the more verbose 'megaparsec' error type.
 type ParsingError = ParseErrorBundle Text Void
 
 -- | Parse a piece of `Text` into either an (Ideal) `SemVer`, a (General)
@@ -757,7 +770,7 @@
 semver' = L.lexeme space semver''
 
 semver'' :: Parsec Void Text SemVer
-semver'' = SemVer <$> majorP <*> minorP <*> patchP <*> preRel <*> metaData
+semver'' = SemVer <$> majorP <*> minorP <*> patchP <*> preRel <*> optional metaData
 
 -- | Parse a group of digits, which can't be lead by a 0, unless it is 0.
 digitsP :: Parsec Void Text Word
@@ -775,19 +788,24 @@
 preRel :: Parsec Void Text [VChunk]
 preRel = (char '-' *> chunks) <|> pure []
 
-metaData :: Parsec Void Text [VChunk]
-metaData = (char '+' *> chunks) <|> pure []
+metaData :: Parsec Void Text Text
+metaData = do
+  void $ char '+'
+  fold . NEL.intersperse "." <$> section `PC.sepBy1` char '.'
+  where
+    section :: Parsec Void Text Text
+    section = takeWhile1P (Just "Metadata char") (\c -> isAlphaNum c || c == '-')
 
 chunksNE :: Parsec Void Text (NonEmpty VChunk)
-chunksNE = chunk `PC.sepBy1` char '.'
+chunksNE = chunkWith unit'  `PC.sepBy1` char '.'
 
 chunks :: Parsec Void Text [VChunk]
-chunks = chunk `sepBy` char '.'
+chunks = chunkWith unit `sepBy` char '.'
 
 -- | Handling @0@ is a bit tricky. We can't allow runs of zeros in a chunk,
 -- since a version like @1.000.1@ would parse as @1.0.1@.
-chunk :: Parsec Void Text VChunk
-chunk = try zeroWithLetters <|> oneZero <|> PC.some (iunit <|> sunit)
+chunkWith :: Parsec Void Text VUnit -> Parsec Void Text VChunk
+chunkWith u = try zeroWithLetters <|> oneZero <|> PC.some u
   where
     oneZero :: Parsec Void Text (NonEmpty VUnit)
     oneZero = (Digits 0 :| []) <$ single '0'
@@ -796,17 +814,28 @@
     zeroWithLetters = do
       z <- Digits 0 <$ single '0'
       s <- PC.some sunit
-      c <- optional chunk
+      c <- optional (chunkWith u)
       case c of
         Nothing -> pure $ NEL.cons z s
         Just c' -> pure $ NEL.cons z s <> c'
 
+unit :: Parsec Void Text VUnit
+unit = iunit <|> sunit
+
+unit' :: Parsec Void Text VUnit
+unit' = iunit <|> sunit'
+
 iunit :: Parsec Void Text VUnit
 iunit = Digits <$> ((0 <$ single '0') <|> (read <$> some digitChar))
 
 sunit :: Parsec Void Text VUnit
-sunit = Str . T.pack <$> some letterChar
+sunit = Str . T.pack <$> some (letterChar <|> single '-')
 
+-- | Same as `sunit`, but don't allow hyphens. Intended for the main body of
+-- `Version`.
+sunit' :: Parsec Void Text VUnit
+sunit' = Str . T.pack <$> some letterChar
+
 -- | Parse a (Haskell) `PVP`, as defined above.
 pvp :: Text -> Either ParsingError PVP
 pvp = parse (pvp' <* eof) "PVP"
@@ -824,7 +853,7 @@
 version' = L.lexeme space version''
 
 version'' :: Parsec Void Text Version
-version'' = Version <$> optional (try epochP) <*> chunksNE <*> metaData <*> preRel
+version'' = Version <$> optional (try epochP) <*> chunksNE <*> preRel <*> optional metaData
 
 epochP :: Parsec Void Text Word
 epochP = read <$> (some digitChar <* char ':')
@@ -845,7 +874,7 @@
 
 mchunk :: Parsec Void Text MChunk
 mchunk = choice [ try $ (\(t, i) -> MDigit i t) <$> match (L.decimal <* next)
-                , try $ (\(t, i) -> MRev i t) <$> (match (single 'r' *> L.decimal <* next))
+                , try $ (\(t, i) -> MRev i t) <$> match (single 'r' *> L.decimal <* next)
                 , MPlain . T.pack <$> some (letterChar <|> digitChar) ]
   where
     next :: Parsec Void Text ()
@@ -875,7 +904,7 @@
   where
     ver = intersperse "." [ showt ma, showt mi, showt pa ]
     pr' = foldable [] ("-" :) $ intersperse "." (chunksAsT pr)
-    me' = foldable [] ("+" :) $ intersperse "." (chunksAsT me)
+    me' = maybe [] (\m -> ["+",m]) me
 
 -- | Convert a `PVP` back to its textual representation.
 prettyPVP :: PVP -> Text
@@ -883,10 +912,10 @@
 
 -- | Convert a `Version` back to its textual representation.
 prettyVer :: Version -> Text
-prettyVer (Version ep cs me pr) = ep' <> mconcat (ver <> me' <> pr')
+prettyVer (Version ep cs pr me) = ep' <> mconcat (ver <> me' <> pr')
   where
     ver = intersperse "." . chunksAsT $ NEL.toList cs
-    me' = foldable [] ("+" :) $ intersperse "." (chunksAsT me)
+    me' = maybe [] (\m -> ["+",m]) me
     pr' = foldable [] ("-" :) $ intersperse "." (chunksAsT pr)
     ep' = maybe "" (\e -> showt e <> ":") ep
 
diff --git a/test/Test.hs b/test/Test.hs
--- a/test/Test.hs
+++ b/test/Test.hs
@@ -6,7 +6,7 @@
 module Main ( main ) where
 
 import           Data.Char (chr)
-import           Data.Either (isLeft)
+import           Data.Either (fromRight, isLeft)
 import           Data.Foldable (fold)
 import           Data.List (groupBy)
 import qualified Data.List.NonEmpty as NEL
@@ -25,7 +25,7 @@
 ---
 
 instance Arbitrary SemVer where
-  arbitrary = SemVer <$> arbitrary <*> arbitrary <*> arbitrary <*> chunks <*> chunks
+  arbitrary = SemVer <$> arbitrary <*> arbitrary <*> arbitrary <*> chunks <*> pure Nothing
 
 -- | Sane generation of VChunks.
 chunks :: Gen [VChunk]
@@ -51,13 +51,14 @@
   arbitrary = Letter . chr <$> choose (97, 122)
 
 instance Arbitrary Version where
-  arbitrary = Version <$> arbitrary <*> chunksNE <*> chunks <*> chunks
+  arbitrary = Version <$> arbitrary <*> chunksNE <*> chunks <*> pure Nothing
 
 -- | These don't need to parse as a SemVer.
 goodVers :: [T.Text]
 goodVers = [ "1", "1.2", "1.0rc0", "1.0rc1", "1.1rc1", "1.58.0-3",  "44.0.2403.157-1"
            , "0.25-2",  "8.u51-1", "21-2", "7.1p1-1", "20150826-1", "1:0.10.16-3"
-           , "1.11.0.git.20200404-1", "1.11.0+20200830-1", "1:3.20" ]
+           , "1.11.0.git.20200404-1", "1.11.0+20200830-1", "1:3.20"
+           ]
 
 badVers :: [T.Text]
 badVers = ["", "1.2 "]
@@ -72,13 +73,16 @@
             ]
 
 badSemVs :: [T.Text]
-badSemVs = [ "1", "1.2", "1.2.3+a1b2bc3.1-alpha.2", "a.b.c", "1.01.1"
-           , "1.2.3+a1b!2c3.1", "", "1.2.3 "
+badSemVs = [ "1", "1.2", "a.b.c", "1.01.1", "1.2.3+a1b!2c3.1", "", "1.2.3 "
            ]
 
 goodSemVs :: [T.Text]
 goodSemVs = [ "0.1.0", "1.2.3", "1.2.3-1", "1.2.3-alpha", "1.2.3-alpha.2"
             , "1.2.3+a1b2c3.1", "1.2.3-alpha.2+a1b2c3.1", "2.2.1-b05"
+            -- Weird Pre-releases
+            , "1.0.0-x-y-z.-"
+            -- Weird metadata
+            , "1.0.0-alpha+001", "1.0.0+21AF26D3---117B344092BD"
             ]
 
 -- | The exact example from `http://semver.org`
@@ -117,13 +121,12 @@
         testCase "1.2.3-alpha.2 == 1.2.3-alpha.2+a1b2c3.1"
         (assertBool "Equality test of two complicated SemVers failed"
          $ semver "1.2.3-alpha.2" == semver "1.2.3-alpha.2+a1b2c3.1") :
-        map (\(a,b) -> testCase (T.unpack $ a <> " < " <> b) $ comp semver a b)
-        (zip semverOrd $ tail semverOrd)
+        zipWith (\a b -> testCase (T.unpack $ a <> " < " <> b) $ comp semver a b) semverOrd (tail semverOrd)
       , testGroup "Whitespace Handling"
-        [ testCase "1.2.3-1[ ]" $ parse semver' "semver whitespace" "1.2.3-1 " @?= Right (SemVer 1 2 3 [[Digits 1]] [])
+        [ testCase "1.2.3-1[ ]" $ parse semver' "semver whitespace" "1.2.3-1 " @?= Right (SemVer 1 2 3 [[Digits 1]] Nothing)
         ]
       , testGroup "Zero Handling"
-        [ testCase "2.2.1-b05" $ semver "2.2.1-b05" @?= Right (SemVer 2 2 1 [[Str "b", Digits 0, Digits 5]] [])
+        [ testCase "2.2.1-b05" $ semver "2.2.1-b05" @?= Right (SemVer 2 2 1 [[Str "b", Digits 0, Digits 5]] Nothing)
 
         ]
       ]
@@ -131,8 +134,7 @@
       [ testGroup "Good PVPs" $
         map (\s -> testCase (T.unpack s) $ isomorphPVP s) cabalOrd
       , testGroup "Comparisons" $
-        map (\(a,b) -> testCase (T.unpack $ a <> " < " <> b) $ comp pvp a b)
-        (zip cabalOrd $ tail cabalOrd)
+        zipWith (\a b -> testCase (T.unpack $ a <> " < " <> b) $ comp pvp a b) cabalOrd (tail cabalOrd)
       ]
     , testGroup "(General) Versions"
       [ testGroup "Good Versions" $
@@ -154,8 +156,7 @@
       , testGroup "Bad Versions (shouldn't parse)" $
         map (\s -> testCase (T.unpack s) $ assertBool "A bad version parsed" $ isLeft $ mess s) badVers
       , testGroup "Comparisons" $
-        map (\(a,b) -> testCase (T.unpack $ a <> " < " <> b) $ comp mess a b) $
-        zip messComps (tail messComps)
+        zipWith (\a b -> testCase (T.unpack $ a <> " < " <> b) $ comp mess a b) messComps (tail messComps)
       , testGroup "SemVer-like Value Extraction"
         [ testCase "messMajor" $
           (hush (mess "1.6.0a+2014+m872b87e73dfb-1") >>= messMajor) @?= Just 1
@@ -174,10 +175,10 @@
         [ testCase "1.2.3 is SemVer" $ check $ isSemVer <$> versioning "1.2.3"
         , testCase "1.2.3-1 is SemVer" $ check $ isSemVer <$> versioning "1.2.3-1"
         , testCase "1.2.3-1+1 is SemVer" $ check $ isSemVer <$> versioning "1.2.3-1+1"
+        , testCase "1.2.3+1-1 is SemVer" $ check $ isSemVer <$> versioning "1.2.3+1-1"
         , testCase "1.2.3r1 is Version" $ check $ isVersion <$> versioning "1.2.3r1"
         , testCase "0.25-2 is Version" $ check $ isVersion <$> versioning "0.25-2"
         , testCase "1:1.2.3-1 is Version" $ check $ isVersion <$> versioning "1:1.2.3-1"
-        , testCase "1.2.3+1-1 is Version" $ check $ isVersion <$> versioning "1.2.3+1-1"
         , testCase "1:3.20.1-1 is Version" $ check $ isVersion <$> versioning "1:3.20.1-1"
         , testCase "000.007-1 is Mess" $ check $ isMess <$> versioning "000.007-1"
         , testCase "20.26.1_0-2 is Mess" $ check $ isMess <$> versioning "20.26.1_0-2"
@@ -221,7 +222,7 @@
       ]
     , testGroup "Megaparsec Behaviour"
       [ testCase "manyTill" $ parse nameGrab "manyTill" "linux-firmware-3.2.14-1-x86_64.pkg.tar.xz" @?= Right "linux-firmware"
-      , testCase "Extracting version" $ parse versionGrab "extraction" "linux-firmware-3.2.14-1-x86_64.pkg.tar.xz" @?= Right(Ideal $ SemVer 3 2 14 [[Digits 1]] [])
+      , testCase "Extracting version" $ parse versionGrab "extraction" "linux-firmware-3.2.14-1-x86_64.pkg.tar.xz" @?= Right(Ideal $ SemVer 3 2 14 [[Digits 1, Str "-x", Digits 86]] Nothing)
       ]
     ]
   ]
@@ -267,7 +268,7 @@
 equal f a = check $ (\r -> r == r) <$> f a
 
 check :: Either a Bool -> Assertion
-check = assertBool "Some Either-based assertion failed" . either (const False) id
+check = assertBool "Some Either-based assertion failed" . fromRight False
 
 isSemVer :: Versioning -> Bool
 isSemVer (Ideal _) = True
@@ -283,8 +284,8 @@
 
 incPatch :: Assertion
 incPatch = (v1 & patch %~ (+ 1)) @?= v2
-  where v1 = Ideal $ SemVer 1 2 3 [] []
-        v2 = Ideal $ SemVer 1 2 4 [] []
+  where v1 = Ideal $ SemVer 1 2 3 [] Nothing
+        v2 = Ideal $ SemVer 1 2 4 [] Nothing
 
 incFromT :: Assertion
 incFromT = (("1.2.3" :: T.Text) & patch %~ (+ 1)) @?= "1.2.4"
diff --git a/versions.cabal b/versions.cabal
--- a/versions.cabal
+++ b/versions.cabal
@@ -1,6 +1,6 @@
 cabal-version:      2.2
 name:               versions
-version:            4.0.3
+version:            5.0.0
 synopsis:           Types and parsers for software version numbers.
 description:
   A library for parsing and comparing software version numbers. We like to give
@@ -19,6 +19,8 @@
   Please switch to <http://semver.org Semantic Versioning> if you aren't
   currently using it. It provides consistency in version incrementing and has
   the best constraints on comparisons.
+  .
+  This library implements version @2.0.0@ of the SemVer spec.
 
 category:           Data
 homepage:           https://github.com/fosskers/versions