diff --git a/appsrc/POSTrainer.hs b/appsrc/POSTrainer.hs
--- a/appsrc/POSTrainer.hs
+++ b/appsrc/POSTrainer.hs
@@ -12,6 +12,7 @@
 import NLP.Types (POSTagger, Error)
 import NLP.Types.IOB
 
+import qualified NLP.Corpora.Brown as B
 import qualified NLP.Corpora.Conll as C
 
 main :: IO ()
@@ -20,18 +21,14 @@
   let output = last args
       corpora = init args
 
-      avgPerTagger :: POSTagger C.Tag
+      avgPerTagger :: POSTagger B.Tag
       avgPerTagger = Avg.mkTagger Avg.emptyPerceptron Nothing
 
-      initTagger :: POSTagger C.Tag
+      initTagger :: POSTagger B.Tag
       initTagger   = UT.mkTagger Map.empty (Just avgPerTagger)
+
   rawCorpus <- mapM T.readFile corpora
-  let eCorpora :: Either Error [[IOBChunk C.Chunk C.Tag]]
-      eCorpora = parseIOB $ T.concat rawCorpus
-  case eCorpora of
-    Left err -> T.putStrLn err
-    Right taggedCorpora -> do
-     let taggedSentences = map toTaggedSentence taggedCorpora
-     tagger <- train initTagger taggedSentences
-     saveTagger tagger output
+  let taggedSentences = B.parseTaggedSentences $ T.concat rawCorpus
+  tagger <- train initTagger taggedSentences
+  saveTagger tagger output
 
diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,13 @@
 = HEAD =
 
+= 0.9.0.0 =
+
+ - Regenerated the model files; changes to cereal caused the old
+   Average Perceptron models to throw exceptions on load, and as such,
+   are no longer compatible.  The packaged models have been updated.
+
+ - Minor updates to slack build script.
+
 = 0.8.0.2 =
 
  - Bounded the version of cereal to < 0.5 because of breaking changes
diff --git a/chatter.cabal b/chatter.cabal
--- a/chatter.cabal
+++ b/chatter.cabal
@@ -1,5 +1,5 @@
 name:                chatter
-version:             0.8.0.2
+version:             0.9.0.0
 synopsis:            A library of simple NLP algorithms.
 description:         chatter is a collection of simple Natural Language
                      Processing algorithms.
@@ -77,7 +77,7 @@
                      containers     >= 0.5.0.0,
                      random-shuffle >= 0.0.4,
                      MonadRandom    >= 0.1.2,
-                     cereal         >= 0.4.0.1 && < 0.5,
+                     cereal         >= 0.4.0.1 && < 0.5.3.0,
                      cereal-text    >= 0.1 && < 0.2,
                      fullstop       >= 0.1.3.1,
                      bytestring     >= 0.10.0.0,
@@ -112,7 +112,7 @@
                      text >= 0.11.3.0,
                      base >= 4.6 && <= 6,
                      bytestring >= 0.10.0.0,
-                     cereal >= 0.4.0.1 && < 0.5
+                     cereal >= 0.4.0.1 && < 0.5.3.0
 
    ghc-options:      -Wall -main-is Tagger -rtsopts
 
@@ -126,7 +126,7 @@
                      text >= 0.11.3.0,
                      base >= 4.6 && <= 6,
                      bytestring >= 0.10.0.0,
-                     cereal >= 0.4.0.1 && < 0.5,
+                     cereal >= 0.4.0.1 && < 0.5.3.0,
                      containers >= 0.5.0.0
 
    ghc-options:      -Wall -main-is POSTrainer -rtsopts
@@ -141,7 +141,7 @@
                      text >= 0.11.3.0,
                      base >= 4.6 && <= 6,
                      bytestring >= 0.10.0.0,
-                     cereal >= 0.4.0.1 && < 0.5,
+                     cereal >= 0.4.0.1 && < 0.5.3.0,
                      containers >= 0.5.0.0
 
    ghc-options:      -Wall -main-is ChunkTrainer -rtsopts
@@ -156,7 +156,7 @@
                      text >= 0.11.3.0,
                      base >= 4.6 && <= 6,
                      bytestring >= 0.10.0.0,
-                     cereal >= 0.4.0.1 && < 0.5,
+                     cereal >= 0.4.0.1 && < 0.5.3.0,
                      containers >= 0.5.0.0
 
    ghc-options:      -Wall -main-is NERTrainer -rtsopts
@@ -172,7 +172,7 @@
                      text >= 0.11.3.0,
                      base >= 4.6 && <= 6,
                      bytestring >= 0.10.0.0,
-                     cereal >= 0.4.0.1 && < 0.5,
+                     cereal >= 0.4.0.1 && < 0.5.3.0,
                      containers >= 0.5.0.0
 
    ghc-options:      -Wall -main-is Evaluate -rtsopts
@@ -226,7 +226,7 @@
                      tokenize,
                      QuickCheck,
                      filepath,
-                     cereal >= 0.4.0.1 && < 0.5,
+                     cereal >= 0.4.0.1 && < 0.5.3.0,
                      quickcheck-instances,
                      containers,
                      tasty,
diff --git a/data/models/README b/data/models/README
--- a/data/models/README
+++ b/data/models/README
@@ -2,17 +2,16 @@
 brown.pos.model.gz
 ---------------------------------------------------------------------
 
-Averaged Perceptron tagger and Unambiguous Tagger trained on most of
-the Brown corpus; the following files were held out for testing:
+Averaged Perceptron tagger and Unambiguous Tagger trained on the Brown corpus.
 
-  ca01 ca03 cb02 cc01 cc03 cd02 ce01 ce03 cf02 cg01 cg03 ch02 cj01 cj03
-  ck02 cl01 cl03 cm02 cn01 cn03 cp02 cr01 cr03 ca02 cb01 cb03 cc02 cd01
-  cd03 ce02 cf01 cf03 cg02 ch01 ch03 cj02 ck01 ck03 cl02 cm01 cm03 cn02
-  cp01 cp03 cr02
+Generated by:
 
-The remainder of the Brown corpus was used to train this model.
+$ time ./dist/build/trainPOS/trainPOS full_brown brown.pos.model
 
+where full_brown is the result of concatenating all the Brown corpus files in ~/nltk_data/corpora/brown:
 
+$ cat ~/nltk_data/corpora/brown/c??? > full_brown
+
 ---------------------------------------------------------------------
 conll2000.pos.model.gz
 ---------------------------------------------------------------------
@@ -45,4 +44,5 @@
 wikiner.ner.model.gz
 ---------------------------------------------------------------------
 
-A Chunker that chunks to NER tags; trained on aij-wikiner-en-wp2
+A Chunker that chunks to NER tags; trained on aij-wikiner-en-wp2 (see: http://schwa.org/projects/resources/wiki/Wikiner)
+
diff --git a/data/models/brown.pos.model.gz b/data/models/brown.pos.model.gz
# file too large to diff: data/models/brown.pos.model.gz
diff --git a/data/models/conll2000.chunk.model.gz b/data/models/conll2000.chunk.model.gz
Binary files a/data/models/conll2000.chunk.model.gz and b/data/models/conll2000.chunk.model.gz differ
diff --git a/data/models/conll2000.pos.model.gz b/data/models/conll2000.pos.model.gz
# file too large to diff: data/models/conll2000.pos.model.gz
diff --git a/data/models/wikiner.ner.model.gz b/data/models/wikiner.ner.model.gz
# file too large to diff: data/models/wikiner.ner.model.gz
diff --git a/src/NLP/Corpora/Brown.hs b/src/NLP/Corpora/Brown.hs
--- a/src/NLP/Corpora/Brown.hs
+++ b/src/NLP/Corpora/Brown.hs
@@ -5,6 +5,8 @@
 module NLP.Corpora.Brown
  ( Tag(..)
  , Chunk(..)
+ , parseTaggedSentences
+   
  )
 where
 
@@ -19,6 +21,12 @@
 
 import qualified NLP.Types.Tags as T
 import NLP.Types.General
+import NLP.Types.Tree hiding (Chunk)
+import NLP.Corpora.Parsing (readPOS)
+
+-- | Parse a Brown corpus into TagagedSentences.
+parseTaggedSentences :: Text -> [TaggedSentence Tag]
+parseTaggedSentences rawCorpus = map readPOS $ T.lines rawCorpus
 
 data Chunk = C_NP -- ^ Noun Phrase.
            | C_VP -- ^ Verb Phrase.
diff --git a/src/NLP/Corpora/Conll.hs b/src/NLP/Corpora/Conll.hs
--- a/src/NLP/Corpora/Conll.hs
+++ b/src/NLP/Corpora/Conll.hs
@@ -15,6 +15,17 @@
 
 import qualified NLP.Types.Tags as T
 import NLP.Types.General
+import NLP.Types.Tree hiding (Chunk)
+import NLP.Types.IOB
+
+-- | Parse an IOB-formatted Conll corpus into TagagedSentences.
+parseTaggedSentences :: Text -> [TaggedSentence Tag]
+parseTaggedSentences rawCorpus =
+  let res :: Either Error [[IOBChunk Chunk Tag]]
+      res = parseIOB rawCorpus
+  in case res of
+       Left            err -> []
+       Right taggedCorpora -> map toTaggedSentence taggedCorpora
 
 -- | Named entity categories defined for the Conll 2003 task.
 data NERTag = PER
diff --git a/src/NLP/POS.hs b/src/NLP/POS.hs
--- a/src/NLP/POS.hs
+++ b/src/NLP/POS.hs
@@ -46,7 +46,7 @@
   )
 where
 
-
+import qualified Control.Exception           as X
 import           Codec.Compression.GZip      (decompress)
 import           Data.ByteString             (ByteString)
 import qualified Data.ByteString             as BS
@@ -118,7 +118,7 @@
 loadTagger file = do
   content <- getContent file
   case deserialize taggerTable content of
-    Left err -> error err
+    Left err -> error ("Could not load tagger from file: "++ file ++" due to error: \n" ++ err)
     Right tgr -> return tgr
   where
     getContent :: FilePath -> IO ByteString