diff --git a/ChangeLog.md b/ChangeLog.md
index 87e64958..1dddb87e 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,11 @@
+## 0.6.1
+
+* Switch to V2 upload by default
+
+## 0.6.0
+
+* Upload bundle V2 stuff
+
 ## 0.5.2
 
 * Upload LTS to Hackage with the name LTSHaskell
diff --git a/Dockerfile b/Dockerfile
index a83c42bc..c3956908 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -14,9 +14,9 @@ ADD debian-bootstrap.sh /tmp/debian-bootstrap.sh
 RUN DEBIAN_FRONTEND=noninteractive bash /tmp/debian-bootstrap.sh
 RUN rm /tmp/debian-bootstrap.sh
 
-RUN DEBIAN_FRONTEND=noninteractive apt-get install -y cabal-install-1.20 ghc-7.8.4
+RUN DEBIAN_FRONTEND=noninteractive apt-get install -y cabal-install-1.20 ghc-7.8.4 alex-3.1.3 happy-1.19.4
 
-ENV PATH /home/stackage/.cabal/bin:/usr/local/sbin:/usr/local/bin:/opt/ghc/7.8.4/bin:/opt/cabal/1.20/bin:/usr/sbin:/usr/bin:/sbin:/bin
+ENV PATH /home/stackage/.cabal/bin:/usr/local/sbin:/usr/local/bin:/opt/ghc/7.8.4/bin:/opt/cabal/1.20/bin:/opt/alex/3.1.3/bin:/opt/happy/1.19.4/bin:/usr/sbin:/usr/bin:/sbin:/bin
 
 RUN cabal update
 ADD . /tmp/stackage
diff --git a/Stackage/BuildConstraints.hs b/Stackage/BuildConstraints.hs
index e7aae355..c4ce1ceb 100644
--- a/Stackage/BuildConstraints.hs
+++ b/Stackage/BuildConstraints.hs
@@ -120,7 +120,7 @@ instance FromJSON PackageConstraints where
         pcBuildBenchmarks <- o .: "build-benchmarks"
         pcFlagOverrides <- Map.mapKeysWith const mkFlagName <$> o .: "flags"
         pcMaintainer <- o .:? "maintainer"
-        pcEnableLibProfile <- fmap (fromMaybe False) (o .:? "library-profiling")
+        pcEnableLibProfile <- fmap (fromMaybe True) (o .:? "library-profiling")
         return PackageConstraints {..}
 
 -- | The proposed plan from the requirements provided by contributors.
diff --git a/Stackage/CompleteBuild.hs b/Stackage/CompleteBuild.hs
index cf74eef2..fb1cdde5 100644
--- a/Stackage/CompleteBuild.hs
+++ b/Stackage/CompleteBuild.hs
@@ -8,6 +8,7 @@ module Stackage.CompleteBuild
     , completeBuild
     , justCheck
     , justUploadNightly
+    , getStackageAuthToken
     ) where
 
 import Control.Concurrent        (threadDelay)
@@ -33,10 +34,14 @@ import System.IO                 (BufferMode (LineBuffering), hSetBuffering)
 -- | Flags passed in from the command line.
 data BuildFlags = BuildFlags
     { bfEnableTests      :: !Bool
+    , bfEnableHaddock    :: !Bool
     , bfDoUpload         :: !Bool
     , bfEnableLibProfile :: !Bool
+    , bfEnableExecDyn    :: !Bool
     , bfVerbose          :: !Bool
     , bfSkipCheck        :: !Bool
+    , bfUploadV1         :: !Bool
+    , bfServer           :: !StackageServer
     } deriving (Show)
 
 data BuildType = Nightly | LTS BumpType
@@ -55,6 +60,8 @@ data Settings = Settings
     , setArgs   :: Text -> UploadBundle -> UploadBundle
     , postBuild :: IO ()
     , distroName :: Text -- ^ distro name on Hackage
+    , snapshotType :: SnapshotType
+    , bundleDest :: FilePath
     }
 
 nightlyPlanFile :: Text -- ^ day
@@ -66,7 +73,7 @@ nightlySettings :: Text -- ^ day
                 -> Settings
 nightlySettings day plan' = Settings
     { planFile = nightlyPlanFile day
-    , buildDir = fpFromText $ "builds/stackage-nightly-" ++ day
+    , buildDir = fpFromText $ "builds/nightly"
     , logDir = fpFromText $ "logs/stackage-nightly-" ++ day
     , title = \ghcVer -> concat
         [ "Stackage Nightly "
@@ -79,6 +86,8 @@ nightlySettings day plan' = Settings
     , plan = plan'
     , postBuild = return ()
     , distroName = "Stackage"
+    , snapshotType = STNightly
+    , bundleDest = fpFromText $ "stackage-nightly-" ++ day ++ ".bundle"
     }
   where
     slug' = "nightly-" ++ day
@@ -119,7 +128,7 @@ getSettings man (LTS bumpType) = do
 
     return Settings
         { planFile = newfile
-        , buildDir = fpFromText $ "builds/stackage-lts-" ++ tshow new
+        , buildDir = fpFromText $ "builds/lts"
         , logDir = fpFromText $ "logs/stackage-lts-" ++ tshow new
         , title = \ghcVer -> concat
             [ "LTS Haskell "
@@ -140,6 +149,10 @@ getSettings man (LTS bumpType) = do
             putStrLn "Pushing to Git repository"
             git ["push"]
         , distroName = "LTSHaskell"
+        , snapshotType =
+            case new of
+                LTSVer x y -> STLTS x y
+        , bundleDest = fpFromText $ "stackage-lts-" ++ tshow new ++ ".bundle"
         }
 
 data LTSVer = LTSVer !Int !Int
@@ -203,7 +216,9 @@ getPerformBuild buildFlags Settings {..} = PerformBuild
     , pbJobs = 8
     , pbGlobalInstall = False
     , pbEnableTests = bfEnableTests buildFlags
+    , pbEnableHaddock = bfEnableHaddock buildFlags
     , pbEnableLibProfiling = bfEnableLibProfile buildFlags
+    , pbEnableExecDyn = bfEnableExecDyn buildFlags
     , pbVerbose = bfVerbose buildFlags
     , pbAllowNewer = bfSkipCheck buildFlags
     }
@@ -227,10 +242,23 @@ completeBuild buildType buildFlags = withManager tlsManagerSettings $ \man -> do
             checkBuildPlan plan
 
     putStrLn "Performing build"
-    performBuild (getPerformBuild buildFlags settings) >>= mapM_ putStrLn
+    let pb = getPerformBuild buildFlags settings
+    performBuild pb >>= mapM_ putStrLn
+
+    putStrLn $ "Creating bundle (v2) at: " ++ fpToText bundleDest
+    createBundleV2 CreateBundleV2
+        { cb2Plan = plan
+        , cb2Type = snapshotType
+        , cb2DocsDir = pbDocDir pb
+        , cb2Dest = bundleDest
+        }
 
     when (bfDoUpload buildFlags) $
-        finallyUpload settings man
+        finallyUpload
+            (not $ bfUploadV1 buildFlags)
+            (bfServer buildFlags)
+            settings
+            man
 
 justUploadNightly
     :: Text -- ^ nightly date
@@ -238,41 +266,64 @@ justUploadNightly
 justUploadNightly day = do
     plan <- decodeFileEither (fpToString $ nightlyPlanFile day)
         >>= either throwM return
-    withManager tlsManagerSettings $ finallyUpload $ nightlySettings day plan
+    withManager tlsManagerSettings $ finallyUpload False def $ nightlySettings day plan
+
+getStackageAuthToken :: IO Text
+getStackageAuthToken = do
+    mtoken <- lookupEnv "STACKAGE_AUTH_TOKEN"
+    case mtoken of
+        Nothing -> decodeUtf8 <$> readFile "/auth-token"
+        Just token -> return $ pack token
 
 -- | The final part of the complete build process: uploading a bundle,
 -- docs and a distro to hackage.
-finallyUpload :: Settings -> Manager -> IO ()
-finallyUpload settings@Settings{..} man = do
+finallyUpload :: Bool -- ^ use v2 upload
+              -> StackageServer
+              -> Settings -> Manager -> IO ()
+finallyUpload useV2 server settings@Settings{..} man = do
     putStrLn "Uploading bundle to Stackage Server"
 
-    mtoken <- lookupEnv "STACKAGE_AUTH_TOKEN"
-    token <-
-        case mtoken of
-            Nothing -> decodeUtf8 <$> readFile "/auth-token"
-            Just token -> return $ pack token
+    token <- getStackageAuthToken
 
-    now <- epochTime
-    let ghcVer = display $ siGhcVersion $ bpSystemInfo plan
-    (ident, mloc) <- flip uploadBundle man $ setArgs ghcVer def
-        { ubContents = serverBundle now (title ghcVer) slug plan
-        , ubAuthToken = token
-        }
-    putStrLn $ "New ident: " ++ unSnapshotIdent ident
-    forM_ mloc $ \loc ->
-        putStrLn $ "Track progress at: " ++ loc
+    if useV2
+        then do
+            res <- flip uploadBundleV2 man UploadBundleV2
+                { ub2Server = server
+                , ub2AuthToken = token
+                , ub2Bundle = bundleDest
+                }
+            putStrLn $ "New snapshot available at: " ++ res
+        else do
+            now <- epochTime
+            let ghcVer = display $ siGhcVersion $ bpSystemInfo plan
+            (ident, mloc) <- flip uploadBundle man $ setArgs ghcVer def
+                { ubContents = serverBundle now (title ghcVer) slug plan
+                , ubAuthToken = token
+                }
+            putStrLn $ "New ident: " ++ unSnapshotIdent ident
+            forM_ mloc $ \loc ->
+                putStrLn $ "Track progress at: " ++ loc
+
+            putStrLn "Uploading docs to Stackage Server"
+            res1 <- tryAny $ uploadDocs UploadDocs
+                { udServer = def
+                , udAuthToken = token
+                , udDocs = pbDocDir pb
+                , udSnapshot = ident
+                } man
+            putStrLn $ "Doc upload response: " ++ tshow res1
+
+            putStrLn "Uploading doc map"
+            tryAny (uploadDocMap UploadDocMap
+                { udmServer = def
+                , udmAuthToken = token
+                , udmSnapshot = ident
+                , udmDocDir = pbDocDir pb
+                , udmPlan = plan
+                } man) >>= print
 
     postBuild `catchAny` print
 
-    putStrLn "Uploading docs to Stackage Server"
-    res1 <- uploadDocs UploadDocs
-        { udServer = def
-        , udAuthToken = token
-        , udDocs = pbDocDir pb
-        , udSnapshot = ident
-        } man
-    putStrLn $ "Doc upload response: " ++ tshow res1
-
     ecreds <- tryIO $ readFile "/hackage-creds"
     case map encodeUtf8 $ words $ decodeUtf8 $ either (const "") id ecreds of
         [username, password] -> do
@@ -280,14 +331,5 @@ finallyUpload settings@Settings{..} man = do
             res2 <- uploadHackageDistroNamed distroName plan username password man
             putStrLn $ "Distro upload response: " ++ tshow res2
         _ -> putStrLn "No creds found, skipping Hackage distro upload"
-
-    putStrLn "Uploading doc map"
-    uploadDocMap UploadDocMap
-        { udmServer = def
-        , udmAuthToken = token
-        , udmSnapshot = ident
-        , udmDocDir = pbDocDir pb
-        , udmPlan = plan
-        } man >>= print
   where
     pb = getPerformBuild (error "finallyUpload.buildFlags") settings
diff --git a/Stackage/GhcPkg.hs b/Stackage/GhcPkg.hs
new file mode 100644
index 00000000..27b7f9e1
--- /dev/null
+++ b/Stackage/GhcPkg.hs
@@ -0,0 +1,104 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+{-# LANGUAGE OverloadedStrings #-}
+-- | General commands related to ghc-pkg.
+
+module Stackage.GhcPkg
+    ( setupPackageDatabase
+    ) where
+
+import           Data.Conduit
+import qualified Data.Conduit.List as CL
+import           Data.Conduit.Process
+import qualified Data.Conduit.Text as CT
+import           Data.Maybe
+import           Data.Text (Text)
+import qualified Data.Text as T
+import           Distribution.Compat.ReadP
+import           Distribution.Package
+import           Distribution.Text (parse)
+import           Filesystem.Path.CurrentOS (FilePath)
+import qualified Filesystem.Path.CurrentOS as FP
+import Data.Map (Map)
+import Data.Version (Version)
+import Stackage.Prelude
+import Filesystem (removeTree)
+
+setupPackageDatabase
+    :: Maybe FilePath -- ^ database location, Nothing if using global DB
+    -> FilePath -- ^ documentation root
+    -> (ByteString -> IO ()) -- ^ logging
+    -> Map PackageName Version -- ^ packages and versions to be installed
+    -> (PackageIdentifier -> IO ()) -- ^ callback to be used when unregistering a package
+    -> IO (Set PackageName) -- ^ packages remaining in the database after cleanup
+setupPackageDatabase mdb docDir log' toInstall onUnregister = do
+    registered1 <- getRegisteredPackages flags
+    forM_ registered1 $ \pi@(PackageIdentifier name version) ->
+        case lookup name toInstall of
+            Just version' | version /= version' -> unregisterPackage log' onUnregister docDir flags pi
+            _ -> return ()
+    broken <- getBrokenPackages flags
+    forM_ broken $ unregisterPackage log' onUnregister docDir flags
+    foldMap (\(PackageIdentifier name _) -> singletonSet name)
+        <$> getRegisteredPackages flags
+  where
+    flags = ghcPkgFlags mdb
+
+ghcPkgFlags :: Maybe FilePath -> [String]
+ghcPkgFlags mdb =
+    "--no-user-package-db" :
+    case mdb of
+        Nothing -> ["--global"]
+        Just fp -> ["--package-db=" ++ fpToString fp]
+
+-- | Get broken packages.
+getBrokenPackages :: [String] -> IO [PackageIdentifier]
+getBrokenPackages flags = do
+    (_,ps) <- sourceProcessWithConsumer
+                  (proc
+                       "ghc-pkg"
+                       ("check" : "--simple-output" : flags))
+                  (CT.decodeUtf8 $= CT.lines $= CL.consume)
+    return (mapMaybe parsePackageIdent (T.words (T.unlines ps)))
+
+-- | Get available packages.
+getRegisteredPackages :: [String] -> IO [PackageIdentifier]
+getRegisteredPackages flags = do
+    (_,ps) <- sourceProcessWithConsumer
+                  (proc
+                       "ghc-pkg"
+                       ("list" : "--simple-output" : flags))
+                  (CT.decodeUtf8 $= CT.lines $= CL.consume)
+    return (mapMaybe parsePackageIdent (T.words (T.unlines ps)))
+
+-- | Parse a package identifier: foo-1.2.3
+parsePackageIdent :: Text -> Maybe PackageIdentifier
+parsePackageIdent = fmap fst .
+    listToMaybe .
+    filter (null . snd) .
+    readP_to_S parse . T.unpack
+
+-- | Unregister a package.
+unregisterPackage :: (ByteString -> IO ()) -- ^ log func
+                  -> (PackageIdentifier -> IO ()) -- ^ callback to be used when unregistering a package
+                  -> FilePath -- ^ doc directory
+                  -> [String] -> PackageIdentifier -> IO ()
+unregisterPackage log' onUnregister docDir flags ident@(PackageIdentifier name _) = do
+    log' $ "Unregistering " ++ encodeUtf8 (display ident) ++ "\n"
+    onUnregister ident
+
+    -- Delete libraries
+    sourceProcessWithConsumer
+        (proc "ghc-pkg" ("describe" : flags ++ [unpack $ display ident]))
+        (CT.decodeUtf8
+         $= CT.lines
+         $= CL.mapMaybe parseLibraryDir
+         $= CL.mapM_ (void . tryIO . removeTree))
+
+    void (readProcessWithExitCode
+              "ghc-pkg"
+              ("unregister": flags ++ ["--force", unpack $ display name])
+              "")
+
+    void $ tryIO $ removeTree $ docDir </> fpFromText (display ident)
+  where
+    parseLibraryDir = fmap fpFromText . stripPrefix "library-dirs: "
diff --git a/Stackage/InstallBuild.hs b/Stackage/InstallBuild.hs
index abe8a14e..757939a7 100644
--- a/Stackage/InstallBuild.hs
+++ b/Stackage/InstallBuild.hs
@@ -28,7 +28,9 @@ data InstallFlags = InstallFlags
     , ifJobs               :: !Int
     , ifGlobalInstall      :: !Bool
     , ifEnableTests        :: !Bool
+    , ifEnableHaddock      :: !Bool
     , ifEnableLibProfiling :: !Bool
+    , ifEnableExecDyn      :: !Bool
     , ifVerbose            :: !Bool
     , ifSkipCheck          :: !Bool
     } deriving (Show)
@@ -48,7 +50,9 @@ getPerformBuild plan InstallFlags{..} =
     , pbJobs               = ifJobs
     , pbGlobalInstall      = ifGlobalInstall
     , pbEnableTests        = ifEnableTests
+    , pbEnableHaddock      = ifEnableHaddock
     , pbEnableLibProfiling = ifEnableLibProfiling
+    , pbEnableExecDyn      = ifEnableExecDyn
     , pbVerbose            = ifVerbose
     , pbAllowNewer         = ifSkipCheck
     }
diff --git a/Stackage/PerformBuild.hs b/Stackage/PerformBuild.hs
index b1682e4e..38bb1250 100644
--- a/Stackage/PerformBuild.hs
+++ b/Stackage/PerformBuild.hs
@@ -19,17 +19,18 @@ import qualified Data.Map                    as Map
 import           Data.NonNull                (fromNullable)
 import           Filesystem                  (canonicalizePath, createTree,
                                               getWorkingDirectory, isDirectory,
-                                              removeTree, rename)
+                                              removeTree, rename, isFile, removeFile)
 import           Filesystem.Path             (parent)
 import qualified Filesystem.Path             as F
 import           Stackage.BuildConstraints
 import           Stackage.BuildPlan
+import           Stackage.GhcPkg
 import           Stackage.PackageDescription
 import           Stackage.Prelude            hiding (pi)
 import           System.Directory            (findExecutable)
 import           System.Environment          (getEnvironment)
 import           System.IO                   (IOMode (WriteMode),
-                                              withBinaryFile)
+                                              openBinaryFile)
 import           System.IO.Temp              (withSystemTempDirectory)
 
 data BuildException = BuildException (Map PackageName BuildFailure) [Text]
@@ -62,7 +63,9 @@ data PerformBuild = PerformBuild
     , pbGlobalInstall :: Bool
     -- ^ Register packages in the global database
     , pbEnableTests        :: Bool
+    , pbEnableHaddock      :: Bool
     , pbEnableLibProfiling :: Bool
+    , pbEnableExecDyn      :: Bool
     , pbVerbose            :: Bool
     , pbAllowNewer         :: Bool
     -- ^ Pass --allow-newer to cabal configure
@@ -89,7 +92,7 @@ waitForDeps toolMap packageMap activeComps bp pi action = do
                 Nothing
                     | isCoreExe exe -> return ()
                     -- https://github.com/jgm/zip-archive/issues/23
-                    -- | otherwise -> throwSTM $ ToolMissing exe
+                    -- - | otherwise -> throwSTM $ ToolMissing exe
                     | otherwise -> return ()
                 Just packages -> ofoldl1' (<|>) packages
     action
@@ -133,6 +136,10 @@ pbLibDir pb = pbInstallDest pb </> "lib"
 pbDataDir pb = pbInstallDest pb </> "share"
 pbDocDir pb = pbInstallDest pb </> "doc"
 
+-- | Directory keeping previous result info
+pbPrevResDir :: PerformBuild -> FilePath
+pbPrevResDir pb = pbInstallDest pb </> "prevres"
+
 performBuild :: PerformBuild -> IO [Text]
 performBuild pb = do
     cwd <- getWorkingDirectory
@@ -160,12 +167,13 @@ performBuild' pb@PerformBuild {..} = withBuildDir $ \builddir -> do
         $ \ClosedStream Inherited Inherited -> return ()
 
     let removeTree' fp = whenM (isDirectory fp) (removeTree fp)
-    mapM_ removeTree' [pbInstallDest, pbLogDir]
+    removeTree' pbLogDir
 
-    forM_ (pbDatabase pb) $ \db -> do
-        createTree $ parent db
-        withCheckedProcess (proc "ghc-pkg" ["init", fpToString db])
-            $ \ClosedStream Inherited Inherited -> return ()
+    forM_ (pbDatabase pb) $ \db ->
+        unlessM (isFile $ db </> "package.cache") $ do
+            createTree $ parent db
+            withCheckedProcess (proc "ghc-pkg" ["init", fpToString db])
+                $ \ClosedStream Inherited Inherited -> return ()
     pbLog $ encodeUtf8 "Copying built-in Haddocks\n"
     copyBuiltInHaddocks (pbDocDir pb)
     pbLog $ encodeUtf8 "Finished copying built-in Haddocks\n"
@@ -186,7 +194,15 @@ performBuild' pb@PerformBuild {..} = withBuildDir $ \builddir -> do
     env <- getEnvironment
     haddockFiles <- newTVarIO mempty
 
-    forM_ packageMap $ \pi -> void $ async $ singleBuild pb SingleBuild
+    registeredPackages <- setupPackageDatabase
+        (pbDatabase pb)
+        (pbDocDir pb)
+        pbLog
+        (ppVersion <$> bpPackages pbPlan)
+        (deletePreviousResults pb)
+
+    forM_ packageMap $ \pi -> void $ async $ singleBuild pb registeredPackages
+      SingleBuild
         { sbSem = sem
         , sbErrsVar = errsVar
         , sbWarningsVar = warningsVar
@@ -248,8 +264,10 @@ data SingleBuild = SingleBuild
     , sbHaddockFiles  :: TVar (Map Text FilePath) -- ^ package-version, .haddock file
     }
 
-singleBuild :: PerformBuild -> SingleBuild -> IO ()
-singleBuild pb@PerformBuild {..} SingleBuild {..} =
+singleBuild :: PerformBuild
+            -> Set PackageName -- ^ registered packages
+            -> SingleBuild -> IO ()
+singleBuild pb@PerformBuild {..} registeredPackages SingleBuild {..} =
       withCounter sbActive
     $ handle updateErrs
     $ (`finally` void (atomically $ tryPutTMVar (piResult sbPackageInfo) False))
@@ -261,22 +279,25 @@ singleBuild pb@PerformBuild {..} SingleBuild {..} =
         let wfd comps =
                 waitForDeps sbToolMap sbPackageMap comps pbPlan sbPackageInfo
                 . withTSem sbSem
-        wfd libComps buildLibrary
+        withUnpacked <- wfd libComps buildLibrary
 
-        wfd testComps runTests
+        wfd testComps (runTests withUnpacked)
 
-    name = display $ piName sbPackageInfo
+    pname = piName sbPackageInfo
+    pident = PackageIdentifier pname (ppVersion $ piPlan sbPackageInfo)
+    name = display pname
     namever = concat
         [ name
         , "-"
         , display $ ppVersion $ piPlan sbPackageInfo
         ]
 
-    runIn wdir outH cmd args =
-        withCheckedProcess cp $ \ClosedStream UseProvidedHandle UseProvidedHandle ->
+    runIn wdir getOutH cmd args = do
+        outH <- getOutH
+        withCheckedProcess (cp outH) $ \ClosedStream UseProvidedHandle UseProvidedHandle ->
             (return () :: IO ())
       where
-        cp = (proc (unpack $ asText cmd) (map (unpack . asText) args))
+        cp outH = (proc (unpack $ asText cmd) (map (unpack . asText) args))
             { cwd = Just $ fpToString wdir
             , std_out = UseHandle outH
             , std_err = UseHandle outH
@@ -302,8 +323,21 @@ singleBuild pb@PerformBuild {..} SingleBuild {..} =
     testRunOut = pbLogDir </> fpFromText namever </> "test-run.out"
 
     wf fp inner' = do
-        createTree $ parent fp
-        withBinaryFile (fpToString fp) WriteMode inner'
+        ref <- newIORef Nothing
+        let cleanup = do
+                mh <- readIORef ref
+                forM_ mh hClose
+            getH = do
+                mh <- readIORef ref
+                case mh of
+                    Just h -> return h
+                    Nothing -> mask_ $ do
+                        createTree $ parent fp
+                        h <- openBinaryFile (fpToString fp) WriteMode
+                        writeIORef ref $ Just h
+                        return h
+
+        inner' getH `finally` cleanup
 
     configArgs = ($ []) $ execWriter $ do
         when pbAllowNewer $ tell' "--allow-newer"
@@ -317,6 +351,7 @@ singleBuild pb@PerformBuild {..} SingleBuild {..} =
         tell' $ "--flags=" ++ flags
         when (pbEnableLibProfiling && pcEnableLibProfile) $
             tell' "--enable-library-profiling"
+        when pbEnableExecDyn $ tell' "--enable-executable-dynamic"
       where
         tell' x = tell (x:)
 
@@ -330,22 +365,40 @@ singleBuild pb@PerformBuild {..} SingleBuild {..} =
 
     PackageConstraints {..} = ppConstraints $ piPlan sbPackageInfo
 
-    buildLibrary = wf libOut $ \outH -> do
+    buildLibrary = wf libOut $ \getOutH -> do
         let run a b = do when pbVerbose $ log' (unwords (a : b))
-                         runChild outH a b
-        log' $ "Unpacking " ++ namever
-        runParent outH "cabal" ["unpack", namever]
+                         runChild getOutH a b
 
-        log' $ "Configuring " ++ namever
-        run "cabal" $ "configure" : configArgs
+        isUnpacked <- newIORef False
+        let withUnpacked inner = do
+                unlessM (readIORef isUnpacked) $ do
+                    log' $ "Unpacking " ++ namever
+                    runParent getOutH "cabal" ["unpack", namever]
+                    writeIORef isUnpacked True
+                inner
 
-        log' $ "Building " ++ namever
-        run "cabal" ["build"]
+        isConfiged <- newIORef False
+        let withConfiged inner = withUnpacked $ do
+                unlessM (readIORef isConfiged) $ do
+                    log' $ "Configuring " ++ namever
+                    run "cabal" $ "configure" : configArgs
+                    writeIORef isConfiged True
+                inner
 
-        log' $ "Copying/registering " ++ namever
-        run "cabal" ["copy"]
-        withMVar sbRegisterMutex $ const $
-            run "cabal" ["register"]
+        prevBuildResult <- getPreviousResult pb Build pident
+        unless (prevBuildResult == PRSuccess) $ withConfiged $ do
+          assert (pname `notMember` registeredPackages) $ do
+            deletePreviousResults pb pident
+
+            log' $ "Building " ++ namever
+            run "cabal" ["build"]
+
+            log' $ "Copying/registering " ++ namever
+            run "cabal" ["copy"]
+            withMVar sbRegisterMutex $ const $
+                run "cabal" ["register"]
+
+            savePreviousResult pb Build pident True
 
         -- Even if the tests later fail, we can allow other libraries to build
         -- on top of our successful results
@@ -355,7 +408,11 @@ singleBuild pb@PerformBuild {..} SingleBuild {..} =
         -- dependency's haddocks before this finishes
         atomically $ putTMVar (piResult sbPackageInfo) True
 
-        when (pcHaddocks /= Don'tBuild && not (null $ sdModules $ ppDesc $ piPlan sbPackageInfo)) $ do
+        prevHaddockResult <- getPreviousResult pb Haddock pident
+        let needHaddock = pbEnableHaddock
+                       && checkPrevResult prevHaddockResult pcHaddocks
+                       && not (null $ sdModules $ ppDesc $ piPlan sbPackageInfo)
+        when needHaddock $ withConfiged $ do
             log' $ "Haddocks " ++ namever
             hfs <- readTVarIO sbHaddockFiles
             let hfsOpts = flip map (mapToList hfs) $ \(pkgVer, hf) -> concat
@@ -389,15 +446,21 @@ singleBuild pb@PerformBuild {..} SingleBuild {..} =
                                    $ modifyTVar sbHaddockFiles
                                    $ insertMap namever newPath
 
+            savePreviousResult pb Haddock pident $ either (const False) (const True) eres
             case (eres, pcHaddocks) of
                 (Left e, ExpectSuccess) -> throwM e
                 (Right (), ExpectFailure) -> warn $ namever ++ ": unexpected Haddock success"
                 _ -> return ()
 
-    runTests = wf testOut $ \outH -> do
-        let run = runChild outH
+        return withUnpacked
 
-        when (pbEnableTests && pcTests /= Don'tBuild) $ do
+    runTests withUnpacked = wf testOut $ \getOutH -> do
+        let run = runChild getOutH
+
+        prevTestResult <- getPreviousResult pb Test pident
+        let needTest = pbEnableTests
+                    && checkPrevResult prevTestResult pcTests
+        when needTest $ withUnpacked $ do
             log' $ "Test configure " ++ namever
             run "cabal" $ "configure" : "--enable-tests" : configArgs
 
@@ -408,6 +471,7 @@ singleBuild pb@PerformBuild {..} SingleBuild {..} =
                 log' $ "Test run " ++ namever
                 run "cabal" ["test", "--log=" ++ fpToText testRunOut]
 
+            savePreviousResult pb Test pident $ either (const False) (const True) eres
             case (eres, pcTests) of
                 (Left e, ExpectSuccess) -> throwM e
                 (Right (), ExpectFailure) -> warn $ namever ++ ": unexpected test success"
@@ -434,16 +498,6 @@ singleBuild pb@PerformBuild {..} SingleBuild {..} =
 renameOrCopy :: FilePath -> FilePath -> IO ()
 renameOrCopy src dest = rename src dest `catchIO` \_ -> copyDir src dest
 
-copyDir :: FilePath -> FilePath -> IO ()
-copyDir src dest =
-    runResourceT $ sourceDirectoryDeep False src $$ mapM_C go
-  where
-    src' = src </> ""
-    go fp = forM_ (F.stripPrefix src' fp) $ \suffix -> do
-        let dest' = dest </> suffix
-        liftIO $ createTree $ parent dest'
-        sourceFile fp $$ (sinkFile dest' :: Sink ByteString (ResourceT IO) ())
-
 copyBuiltInHaddocks :: FilePath -> IO ()
 copyBuiltInHaddocks docdir = do
     mghc <- findExecutable "ghc"
@@ -453,3 +507,52 @@ copyBuiltInHaddocks docdir = do
             src <- canonicalizePath
                 (parent (fpFromString ghc) </> "../share/doc/ghc/html/libraries")
             copyDir src docdir
+
+------------- Previous results
+
+-- | The previous actions that can be run
+data ResultType = Build | Haddock | Test
+    deriving (Show, Enum, Eq, Ord, Bounded, Read)
+
+-- | The result generated on a previous run
+data PrevResult = PRNoResult | PRSuccess | PRFailure
+    deriving (Show, Enum, Eq, Ord, Bounded, Read)
+
+-- | Check if we should rerun based on a PrevResult and the expected status
+checkPrevResult :: PrevResult -> TestState -> Bool
+checkPrevResult _          Don'tBuild    = False
+checkPrevResult PRNoResult _             = True
+checkPrevResult PRSuccess  _             = False
+checkPrevResult PRFailure  ExpectSuccess = True
+checkPrevResult PRFailure  _             = False
+
+withPRPath :: PerformBuild -> ResultType -> PackageIdentifier -> (FilePath -> IO a) -> IO a
+withPRPath pb rt ident inner = do
+    createTree $ parent fp
+    inner fp
+  where
+    fp = pbPrevResDir pb </> fpFromString (show rt) </> fpFromText (display ident)
+
+successBS, failureBS :: ByteString
+successBS = "success"
+failureBS = "failure"
+
+getPreviousResult :: PerformBuild -> ResultType -> PackageIdentifier -> IO PrevResult
+getPreviousResult w x y = withPRPath w x y $ \fp -> do
+    eres <- tryIO $ readFile fp
+    return $ case eres of
+        Right bs
+            | bs == successBS -> PRSuccess
+            | bs == failureBS -> PRFailure
+        _                     -> PRNoResult
+
+savePreviousResult :: PerformBuild -> ResultType -> PackageIdentifier -> Bool -> IO ()
+savePreviousResult pb rt ident res =
+    withPRPath pb rt ident $ \fp -> writeFile fp $
+        if res then successBS else failureBS
+
+deletePreviousResults :: PerformBuild -> PackageIdentifier -> IO ()
+deletePreviousResults pb name =
+    forM_ [minBound..maxBound] $ \rt ->
+    withPRPath pb rt name $ \fp ->
+    void $ tryIO $ removeFile fp
diff --git a/Stackage/Prelude.hs b/Stackage/Prelude.hs
index ab2187fc..28fff061 100644
--- a/Stackage/Prelude.hs
+++ b/Stackage/Prelude.hs
@@ -20,6 +20,9 @@ import           Distribution.Version            as X (Version (..),
                                                        VersionRange)
 import           Distribution.Version            as X (withinRange)
 import qualified Distribution.Version            as C
+import           Filesystem                      (createTree)
+import           Filesystem.Path                 (parent)
+import qualified Filesystem.Path                 as F
 
 unPackageName :: PackageName -> Text
 unPackageName (PackageName str) = pack str
@@ -101,3 +104,13 @@ topologicalSort toFinal toDeps =
 data TopologicalSortException key = NoEmptyDeps (Map key (Set key))
     deriving (Show, Typeable)
 instance (Show key, Typeable key) => Exception (TopologicalSortException key)
+
+copyDir :: FilePath -> FilePath -> IO ()
+copyDir src dest =
+    runResourceT $ sourceDirectoryDeep False src $$ mapM_C go
+  where
+    src' = src </> ""
+    go fp = forM_ (F.stripPrefix src' fp) $ \suffix -> do
+        let dest' = dest </> suffix
+        liftIO $ createTree $ parent dest'
+        sourceFile fp $$ (sinkFile dest' :: Sink ByteString (ResourceT IO) ())
diff --git a/Stackage/ServerBundle.hs b/Stackage/ServerBundle.hs
index 6cdf5cb4..5aedb090 100644
--- a/Stackage/ServerBundle.hs
+++ b/Stackage/ServerBundle.hs
@@ -7,21 +7,31 @@ module Stackage.ServerBundle
     , epochTime
     , bpAllPackages
     , docsListing
+    , createBundleV2
+    , CreateBundleV2 (..)
+    , SnapshotType (..)
+    , writeIndexStyle
+    , DocMap
+    , PackageDocs (..)
     ) where
 
 import qualified Codec.Archive.Tar         as Tar
 import qualified Codec.Archive.Tar.Entry   as Tar
 import qualified Codec.Compression.GZip    as GZip
 import qualified Data.Map                  as M
+import           Data.Aeson (ToJSON (..), (.=), object, FromJSON (..), (.:), withObject)
+import System.IO.Temp (withTempDirectory)
 import qualified Data.Yaml                 as Y
-import           Filesystem                (isFile)
+import           Filesystem                (isFile, getWorkingDirectory, listDirectory, isDirectory, canonicalizePath)
 import           Foreign.C.Types           (CTime (CTime))
 import           Stackage.BuildConstraints
 import           Stackage.BuildPlan
 import           Stackage.Prelude
+import           System.IO.Temp (withTempDirectory)
 import qualified System.PosixCompat.Time   as PC
 import qualified Text.XML                  as X
 import           Text.XML.Cursor
+import System.PosixCompat.Files (createSymbolicLink)
 
 -- | Get current time
 epochTime :: IO Tar.EpochTime
@@ -73,13 +83,30 @@ serverBundle time title slug bp@BuildPlan {..} = GZip.compress $ Tar.write
             map (\(PackageName name) -> name)
                 (M.keys $ siCorePackages bpSystemInfo)
 
+-- | Package name is key
+type DocMap = Map Text PackageDocs
+data PackageDocs = PackageDocs
+    { pdVersion :: Text
+    , pdModules :: Map Text [Text]
+    -- ^ module name, path
+    }
+instance ToJSON PackageDocs where
+    toJSON PackageDocs {..} = object
+        [ "version" .= pdVersion
+        , "modules" .= pdModules
+        ]
+instance FromJSON PackageDocs where
+    parseJSON = withObject "PackageDocs" $ \o -> PackageDocs
+        <$> o .: "version"
+        <*> o .: "modules"
+
 docsListing :: BuildPlan
             -> FilePath -- ^ docs directory
-            -> IO ByteString
+            -> IO DocMap
 docsListing bp docsDir =
-    fmap (Y.encode . fold) $ mapM go $ mapToList $ bpAllPackages bp
+    fmap fold $ mapM go $ mapToList $ bpAllPackages bp
   where
-    go :: (PackageName, Version) -> IO (Map Text Y.Value)
+    go :: (PackageName, Version) -> IO DocMap
     go (package, version) = do -- handleAny (const $ return mempty) $ do
         let dirname = fpFromText (concat
                 [ display package
@@ -107,8 +134,138 @@ docsListing bp docsDir =
                     return $ if e
                         then asMap $ singletonMap name [fpToText dirname, href]
                         else mempty
-                return $ singletonMap (display package) $ Y.object
-                    [ "version" Y..= display version
-                    , "modules" Y..= m
-                    ]
+                return $ singletonMap (display package) $ PackageDocs
+                    { pdVersion = display version
+                    , pdModules = m
+                    }
             else return mempty
+
+data SnapshotType = STNightly
+                  | STLTS !Int !Int -- ^ major, minor
+    deriving (Show, Read, Eq, Ord)
+
+instance ToJSON SnapshotType where
+    toJSON STNightly = object
+        [ "type" .= asText "nightly"
+        ]
+    toJSON (STLTS major minor) = object
+        [ "type" .= asText "lts"
+        , "major" .= major
+        , "minor" .= minor
+        ]
+instance FromJSON SnapshotType where
+    parseJSON = withObject "SnapshotType" $ \o -> do
+        t <- o .: "type"
+        case asText t of
+            "nightly" -> return STNightly
+            "lts" -> STLTS
+                <$> o .: "major"
+                <*> o .: "minor"
+            _ -> fail $ "Unknown type for SnapshotType: " ++ unpack t
+
+data CreateBundleV2 = CreateBundleV2
+    { cb2Plan :: BuildPlan
+    , cb2Type :: SnapshotType
+    , cb2DocsDir :: FilePath
+    , cb2Dest :: FilePath
+    }
+
+-- | Create a V2 bundle, which contains the build plan, metadata, docs, and doc
+-- map.
+createBundleV2 :: CreateBundleV2 -> IO ()
+createBundleV2 CreateBundleV2 {..} = do
+    docsDir <- canonicalizePath cb2DocsDir
+    docMap <- docsListing cb2Plan cb2DocsDir
+
+    Y.encodeFile (fpToString $ docsDir </> "build-plan.yaml") cb2Plan
+    Y.encodeFile (fpToString $ docsDir </> "build-type.yaml") cb2Type
+    Y.encodeFile (fpToString $ docsDir </> "docs-map.yaml") docMap
+    void $ writeIndexStyle Nothing cb2DocsDir
+
+    currentDir <- getWorkingDirectory
+    files <- listDirectory docsDir
+
+    let args = "cfJ"
+             : fpToString (currentDir </> cb2Dest)
+             : "--dereference"
+             : map (fpToString . filename) files
+        cp = (proc "tar" args) { cwd = Just $ fpToString docsDir }
+    withCheckedProcess cp $ \ClosedStream Inherited Inherited -> return ()
+
+writeIndexStyle :: Maybe Text -- ^ snapshot id
+                -> FilePath -- ^ docs dir
+                -> IO [String]
+writeIndexStyle msnapid dir = do
+    dirs <- fmap sort
+          $ runResourceT
+          $ sourceDirectory dir
+         $$ filterMC (liftIO . isDirectory)
+         =$ mapC (fpToString . filename)
+         =$ sinkList
+    writeFile (dir </> "index.html") $ mkIndex
+        (unpack <$> msnapid)
+        dirs
+    writeFile (dir </> "style.css") styleCss
+    return dirs
+
+mkIndex :: Maybe String -> [String] -> String
+mkIndex msnapid dirs = concat
+    [ "<!DOCTYPE html>\n<html lang='en'><head><title>Haddocks index</title>"
+    , "<link rel='stylesheet' href='https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css'>"
+    , "<link rel='stylesheet' href='style.css'>"
+    , "<link rel='shortcut icon' href='http://www.stackage.org/static/img/favicon.ico' />"
+    , "</head>"
+    , "<body><div class='container'>"
+    , "<div class='row'><div class='span12 col-md-12'>"
+    , "<h1>Haddock documentation index</h1>"
+    , flip foldMap msnapid $ \snapid -> concat
+        [ "<p class='return'><a href=\"http://www.stackage.org/stackage/"
+        , snapid
+        , "\">Return to snapshot</a></p>"
+        ]
+    , "<ul>"
+    , concatMap toLI dirs
+    , "</ul></div></div></div></body></html>"
+    ]
+  where
+    toLI name = concat
+        [ "<li><a href='"
+        , name
+        , "/index.html'>"
+        , name
+        , "</a></li>"
+        ]
+
+styleCss :: String
+styleCss = concat
+    [ "@media (min-width: 530px) {"
+    , "ul { -webkit-column-count: 2; -moz-column-count: 2; column-count: 2 }"
+    , "}"
+    , "@media (min-width: 760px) {"
+    , "ul { -webkit-column-count: 3; -moz-column-count: 3; column-count: 3 }"
+    , "}"
+    , "ul {"
+    , "  margin-left: 0;"
+    , "  padding-left: 0;"
+    , "  list-style-type: none;"
+    , "}"
+    , "body {"
+    , "  background: #f0f0f0;"
+    , "  font-family: 'Lato', sans-serif;"
+    , "  text-shadow: 1px 1px 1px #ffffff;"
+    , "  font-size: 20px;"
+    , "  line-height: 30px;"
+    , "  padding-bottom: 5em;"
+    , "}"
+    , "h1 {"
+    , "  font-weight: normal;"
+    , "  color: #06537d;"
+    , "  font-size: 45px;"
+    , "}"
+    , ".return a {"
+    , "  color: #06537d;"
+    , "  font-style: italic;"
+    , "}"
+    , ".return {"
+    , "  margin-bottom: 1em;"
+    , "}"]
diff --git a/Stackage/Upload.hs b/Stackage/Upload.hs
index c3e544e4..64d21094 100644
--- a/Stackage/Upload.hs
+++ b/Stackage/Upload.hs
@@ -14,17 +14,26 @@ module Stackage.Upload
     , uploadHackageDistroNamed
     , UploadDocMap (..)
     , uploadDocMap
+    , uploadBundleV2
+    , UploadBundleV2 (..)
+    , def
+    , StackageServer
+    , unStackageServer
     ) where
 
 import Control.Monad.Writer.Strict           (execWriter, tell)
 import Data.Default.Class                    (Default (..))
+import Data.Function                         (fix)
 import Filesystem                            (isDirectory, isFile)
 import Network.HTTP.Client
+import qualified Network.HTTP.Client.Conduit as HCC
 import Network.HTTP.Client.MultipartFormData
 import Stackage.BuildPlan                    (BuildPlan)
 import Stackage.Prelude
-import Stackage.ServerBundle                 (bpAllPackages, docsListing)
+import Stackage.ServerBundle                 (bpAllPackages, docsListing, writeIndexStyle)
 import System.IO.Temp                        (withSystemTempFile)
+import qualified System.IO as IO
+import qualified Data.Yaml as Y
 
 newtype StackageServer = StackageServer { unStackageServer :: Text }
     deriving (Show, Eq, Ord, Hashable, IsString)
@@ -107,17 +116,7 @@ uploadDocs (UploadDocs (StackageServer host) fp0 token ident) man = do
   where
     uploadDocsDir = withSystemTempFile "haddocks.tar.xz" $ \fp h -> do
         hClose h
-        dirs <- fmap sort
-              $ runResourceT
-              $ sourceDirectory fp0
-             $$ filterMC (liftIO . isDirectory)
-             =$ mapC (fpToString . filename)
-             =$ sinkList
-        writeFile (fp0 </> "index.html") $ mkIndex
-            (unpack $ unSnapshotIdent ident)
-            dirs
-        writeFile (fp0 </> "style.css") styleCss
-        -- FIXME write index.html, style.css
+        dirs <- writeIndexStyle (Just $ unSnapshotIdent ident) fp0
         let cp = (proc "tar" $ "cJf" : fp : "index.html" : "style.css" : dirs)
                 { cwd = Just $ fpToString fp0
                 }
@@ -201,7 +200,7 @@ uploadDocMap :: UploadDocMap -> Manager -> IO (Response LByteString)
 uploadDocMap UploadDocMap {..} man = do
     docmap <- docsListing udmPlan udmDocDir
     req1 <- parseUrl $ unpack $ unStackageServer udmServer ++ "/upload-doc-map"
-    req2 <- formDataBody (formData docmap) req1
+    req2 <- formDataBody (formData $ Y.encode docmap) req1
     let req3 = req2
             { method = "PUT"
             , requestHeaders =
@@ -219,61 +218,55 @@ uploadDocMap UploadDocMap {..} man = do
         , partFileRequestBody "docmap" "docmap" $ RequestBodyBS docmap
         ]
 
-mkIndex :: String -> [String] -> String
-mkIndex snapid dirs = concat
-    [ "<!DOCTYPE html>\n<html lang='en'><head><title>Haddocks index</title>"
-    , "<link rel='stylesheet' href='https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css'>"
-    , "<link rel='stylesheet' href='style.css'>"
-    , "<link rel='shortcut icon' href='http://www.stackage.org/static/img/favicon.ico' />"
-    , "</head>"
-    , "<body><div class='container'>"
-    , "<div class='row'><div class='span12 col-md-12'>"
-    , "<h1>Haddock documentation index</h1>"
-    , "<p class='return'><a href=\"http://www.stackage.org/stackage/"
-    , snapid
-    , "\">Return to snapshot</a></p><ul>"
-    , concatMap toLI dirs
-    , "</ul></div></div></div></body></html>"
-    ]
-  where
-    toLI name = concat
-        [ "<li><a href='"
-        , name
-        , "/index.html'>"
-        , name
-        , "</a></li>"
-        ]
+data UploadBundleV2 = UploadBundleV2
+    { ub2Server :: StackageServer
+    , ub2AuthToken :: Text
+    , ub2Bundle :: FilePath
+    }
 
-styleCss :: String
-styleCss = concat
-    [ "@media (min-width: 530px) {"
-    , "ul { -webkit-column-count: 2; -moz-column-count: 2; column-count: 2 }"
-    , "}"
-    , "@media (min-width: 760px) {"
-    , "ul { -webkit-column-count: 3; -moz-column-count: 3; column-count: 3 }"
-    , "}"
-    , "ul {"
-    , "  margin-left: 0;"
-    , "  padding-left: 0;"
-    , "  list-style-type: none;"
-    , "}"
-    , "body {"
-    , "  background: #f0f0f0;"
-    , "  font-family: 'Lato', sans-serif;"
-    , "  text-shadow: 1px 1px 1px #ffffff;"
-    , "  font-size: 20px;"
-    , "  line-height: 30px;"
-    , "  padding-bottom: 5em;"
-    , "}"
-    , "h1 {"
-    , "  font-weight: normal;"
-    , "  color: #06537d;"
-    , "  font-size: 45px;"
-    , "}"
-    , ".return a {"
-    , "  color: #06537d;"
-    , "  font-style: italic;"
-    , "}"
-    , ".return {"
-    , "  margin-bottom: 1em;"
-    , "}"]
+uploadBundleV2 :: UploadBundleV2 -> Manager -> IO Text
+uploadBundleV2 UploadBundleV2 {..} man = IO.withBinaryFile (fpToString ub2Bundle) IO.ReadMode $ \h -> do
+    size <- IO.hFileSize h
+    putStrLn $ "Bundle size: " ++ tshow size
+    req1 <- parseUrl $ unpack $ unStackageServer ub2Server ++ "/upload2"
+    let req2 = req1
+            { method = "PUT"
+            , requestHeaders =
+                [ ("Authorization", encodeUtf8 ub2AuthToken)
+                , ("Accept", "application/json")
+                , ("Content-Type", "application/x-tar")
+                ]
+            , requestBody = HCC.requestBodySource (fromIntegral size)
+                          $ sourceHandle h $= printProgress size
+            }
+        sink = decodeUtf8C =$ fix (\loop -> do
+            mx <- peekC
+            case mx of
+                Nothing -> error $ "uploadBundleV2: premature end of stream"
+                Just _ -> do
+                    l <- lineC $ takeCE 4096 =$ foldC
+                    let (cmd, msg') = break (== ':') l
+                        msg = dropWhile (== ' ') $ dropWhile (== ':') msg'
+                    case cmd of
+                        "CONT" -> do
+                            putStrLn msg
+                            loop
+                        "FAILURE" -> error $ "uploadBundleV2 failed: " ++ unpack msg
+                        "SUCCESS" -> return msg
+                        _ -> error $ "uploadBundleV2: unknown command " ++ unpack cmd
+            )
+    withResponse req2 man $ \res -> HCC.bodyReaderSource (responseBody res) $$ sink
+  where
+    printProgress total =
+        loop 0 0
+      where
+        loop sent lastPercent =
+            await >>= maybe (putStrLn "Upload complete") go
+          where
+            go bs = do
+                yield bs
+                let sent' = sent + fromIntegral (length bs)
+                    percent = sent' * 100 `div` total
+                when (percent /= lastPercent)
+                    $ putStrLn $ "Upload progress: " ++ tshow percent ++ "%"
+                loop sent' percent
diff --git a/app/stackage.hs b/app/stackage.hs
index 8fdd2833..75e83108 100644
--- a/app/stackage.hs
+++ b/app/stackage.hs
@@ -10,7 +10,11 @@ import Options.Applicative
 import Filesystem.Path.CurrentOS (decodeString)
 import Paths_stackage (version)
 import Stackage.CompleteBuild
+import Stackage.Upload
 import Stackage.InstallBuild
+import Network.HTTP.Client (withManager)
+import Network.HTTP.Client.TLS (tlsManagerSettings)
+import qualified Data.Text as T
 
 main :: IO ()
 main =
@@ -62,7 +66,13 @@ main =
                   installBuild
                   installFlags
                   "install"
-                  "Install a snapshot from an existing build plan"]
+                  "Install a snapshot from an existing build plan"
+            , cmnd
+                  uploadv2
+                  uploadv2Flags
+                  "upload2"
+                  "Upload a pre-existing v2 bundle"
+            ]
 
     cmnd exec parse name desc =
         command name $
@@ -77,6 +87,11 @@ main =
             (switch
                  (long "skip-tests" <>
                   help "Skip build and running the test suites")) <*>
+        fmap
+            not
+            (switch
+                 (long "skip-haddock" <>
+                  help "Skip generating haddock documentation")) <*>
         fmap
             not
             (switch
@@ -85,12 +100,23 @@ main =
         switch
             (long "enable-library-profiling" <>
              help "Enable profiling when building") <*>
+        switch
+            (long "enable-executable-dynamic" <>
+             help "Enable dynamic executables when building") <*>
         switch
             (long "verbose" <> short 'v' <>
              help "Output verbose detail about the build steps") <*>
         switch
             (long "skip-check" <>
-             help "Skip the check phase, and pass --allow-newer to cabal configure")
+             help "Skip the check phase, and pass --allow-newer to cabal configure") <*>
+        switch
+            (long "upload-v1" <>
+             help "Use the V1 upload code") <*>
+        (fmap fromString (strOption
+            (long "server-url" <>
+             metavar "SERVER-URL" <>
+             showDefault <> value (T.unpack $ unStackageServer def) <>
+             help "Server to upload bundle to")))
 
     nightlyUploadFlags = fromString <$> strArgument
         (metavar "DATE" <>
@@ -136,12 +162,39 @@ main =
             (switch
                 (long "skip-tests" <>
                  help "Skip build and running the test suites")) <*>
+        fmap
+            not
+            (switch
+                 (long "skip-haddock" <>
+                  help "Skip generating haddock documentation")) <*>
         switch
             (long "enable-library-profiling" <>
              help "Enable profiling when building") <*>
+        switch
+            (long "enable-executable-dynamic" <>
+             help "Enable dynamic executables when building") <*>
         switch
             (long "verbose" <> short 'v' <>
              help "Output verbose detail about the build steps") <*>
         switch
             (long "skip-check" <>
              help "Skip the check phase, and pass --allow-newer to cabal configure")
+
+    uploadv2 (path, url) = withManager tlsManagerSettings $ \man -> do
+        token <- getStackageAuthToken
+        res <- flip uploadBundleV2 man UploadBundleV2
+            { ub2AuthToken = token
+            , ub2Server = fromString url
+            , ub2Bundle = decodeString path
+            }
+        putStrLn $ "New URL: " ++ T.unpack res
+
+    uploadv2Flags = (,)
+        <$> (strArgument
+                (metavar "BUNDLE-PATH" <>
+                 help "Bundle path"))
+        <*> strOption
+                (long "server-url" <>
+                 metavar "SERVER-URL" <>
+                 showDefault <> value (T.unpack $ unStackageServer def) <>
+                 help "Server to upload bundle to")
diff --git a/build-constraints.yaml b/build-constraints.yaml
index 74b60e4b..ce127ee5 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -379,6 +379,7 @@ packages:
         - pipes
         - pipes-parse
         - pipes-concurrency
+        - pipes-safe
 
     "Chris Allen <cma@bitemyapp.com>":
         - bloodhound
@@ -390,9 +391,12 @@ packages:
         - fay-jquery
         - fay-text
         - fay-uri
-        - fclabels
         - snaplet-fay
 
+    "Sebastiaan Visser <haskell@fvisser.nl>":
+        - clay
+        - fclabels
+
     "Rodrigo Setti <rodrigosetti@gmail.com>":
         - messagepack
         - messagepack-rpc
@@ -473,7 +477,8 @@ packages:
         - openpgp-asciiarmor
         - MusicBrainz
         - DAV
-        - hopenpgp-tools
+        # https://github.com/fpco/stackage/issues/463
+        #- hopenpgp-tools
 
     # https://github.com/fpco/stackage/issues/160
     "Ketil Malde":
@@ -503,9 +508,9 @@ packages:
         - code-builder
         - fay-builder
         - generic-aeson
+        - generic-xmlpickler
         - hxt-pickle-utils
         - imagesize-conduit
-        - imagesize-conduit
         - json-schema
         - multipart
         - regular-xmlpickler
@@ -518,8 +523,6 @@ packages:
         - rest-types
         - rest-wai
         - tostring
-        - tostring
-        - uri-encode
         - uri-encode
 
     "Simon Michael <simon@joyful.com>":
@@ -529,7 +532,10 @@ packages:
         - io-manager
 
     "Dimitri Sabadie <dimitri.sabadie@gmail.com":
+        # https://github.com/fpco/stackage/pull/461#issuecomment-76914158
+        # - al
         - monad-journal
+        - smoothie
 
     "Thomas Schilling <nominolo@googlemail.com>":
         - ghc-syb-utils
@@ -574,6 +580,7 @@ packages:
         - haddock-api
         - here
         - hlibgit2
+        - gitlib-libgit2
         - hostname-validate
         - interpolatedstring-perl6
         - iproute
@@ -612,6 +619,9 @@ packages:
        - Spock
        - Spock-digestive
        - Spock-worker
+       - users
+       - users-test
+       - users-postgresql-simple
 
     "Joey Eremondi <joey@eremondi.com>":
         - aeson-pretty
@@ -641,6 +651,11 @@ packages:
     "Samplecount stefan@samplecount.com @kaoskorobase":
         - shake-language-c
 
+    "Marcin Mrotek <marcin.jan.mrotek@gmail.com>":
+        - diagrams-hsqml
+        - type-list
+        - vinyl-utils
+
     "Marcin Mrotek <marcin.jan.mrotek@gmail.com>":
         - type-list
 
@@ -703,19 +718,37 @@ packages:
     "Gabríel Arthúr Pétursson gabriel@system.is":
         - sdl2
 
-    "Stackage upper bounds":
+    "Leon Mergen leon@solatis.com @solatis":
+        - network-attoparsec
+        - network-anonymous-i2p
 
-        # https://github.com/fpco/stackage/issues/291
-        - random < 1.0.1.3
+    "Timothy Jones git@zmthy.io @zmthy":
+        - cabal-test-quickcheck
+        - http-media
+
+    "Greg V greg@unrelenting.technology @myfreeweb":
+        - gitson
+        - pcre-heavy
+
+    "Francesco Mazzoli f@mazzo.li @bitonic":
+        - language-c-quote
+
+    "Sönke Hahn soenkehahn@gmail.com @soenkehahn":
+        - string-conversions
+
+    "Oleg Grenrus oleg.grenrus@iki.fi @phadej":
+        - waitra
+    
+    "Adam C. Foltzer acfoltzer@galois.com @acfoltzer":
+        - gitrev
+
+    "Stackage upper bounds":
 
         # https://github.com/fpco/stackage/issues/390
         # NOTE: When this issue is resolved, remove the expected test failure
         # for language-ecmascript as well.
         - language-ecmascript < 0.17
 
-        # https://github.com/fpco/stackage/issues/402
-        - vector-space < 0.9
-
         # https://github.com/fpco/stackage/issues/407
         - HStringTemplate < 0.8
 
@@ -731,22 +764,32 @@ packages:
         # https://github.com/fpco/stackage/issues/426
         - utf8-string < 1
 
-        # https://github.com/d12frosted/CanonicalPath/issues/3
-        - system-canonicalpath < 0.3
-
         # https://github.com/fpco/stackage/issues/440
         - th-orphans < 0.9
         - file-location < 0.4.7
+        - th-desugar < 1.5.1
 
         # https://github.com/fpco/stackage/issues/442
         - blaze-builder < 0.4
+        - blaze-markup < 0.7
+        - blaze-html < 0.8
 
         # https://github.com/fpco/stackage/issues/443
         - exceptions < 0.7
-        - resourcet < 1.1.4
+        - rest-client < 0.5
+        - rest-types < 1.13
+        - rest-core < 0.35
+        - rest-gen < 0.17
+        - rest-wai < 0.1.0.7
 
-        # https://github.com/fpco/stackage/issues/445
-        - semigroupoids < 4.3
+        # https://github.com/fpco/stackage/issues/467
+        - lens < 4.8
+
+        # https://github.com/fpco/stackage/issues/476
+        - vector-space < 0.10
+
+        # https://github.com/ekmett/linear/issues/70
+        - linear < 1.18
 
 # Package flags are applied to individual packages, and override the values of
 # global-flags
@@ -918,9 +961,6 @@ expected-test-failures:
     # https://github.com/BioHaskell/octree/issues/4
     - Octree
 
-    # https://github.com/goldfirere/th-desugar/issues/12
-    - th-desugar
-
     # https://github.com/jmillikin/haskell-filesystem/issues/3
     - system-filepath
 
@@ -993,20 +1033,52 @@ expected-test-failures:
     # https://github.com/haskell-distributed/distributed-process-execution/issues/2
     - distributed-process-execution
 
+    # Seems to depend on mtl being installed in user package database, which
+    # isn't always the case (e.g., build server)
+    - happy
+
+    # https://github.com/jberryman/directory-tree/issues/4
+    - directory-tree
+
+    # https://github.com/zmthy/http-media/issues/11
+    - http-media
+
+    # https://github.com/ekmett/semigroupoids/issues/18
+    - semigroupoids
+
+    # https://github.com/ndmitchell/hoogle/issues/101
+    - hoogle
+
+    # https://github.com/myfreeweb/gitson/issues/1
+    - gitson
+
+    # https://github.com/jcristovao/enclosed-exceptions/issues/6
+    - enclosed-exceptions
+
+    # Expects a running PostgreSQL server
+    - users-postgresql-simple
+
+    # Problems with linking with system libraries on Ubuntu 12.04
+    - nettle
+
+    # Requires locally running services
+    - network-anonymous-i2p
+
 # Haddocks which are expected to fail. Same concept as expected test failures.
 expected-haddock-failures:
     # https://github.com/acw/bytestring-progress/issues/4
     - bytestring-progress
 
-    # https://github.com/ekmett/gl/issues/4
-    - gl
-
     # https://github.com/leventov/yarr/issues/5
     - yarr
 
     # https://github.com/wereHamster/rethinkdb-client-driver/issues/1
     - rethinkdb-client-driver
 
+    # Requires build before haddock, which doesn't always happen in incremental
+    # builds. Could consider special-casing this requirement.
+    - gtk
+
 # Benchmarks which should not be built. Note that Stackage does *not* generally
 # build benchmarks. The difference here will be whether dependencies for these
 # benchmarks are included or not.
diff --git a/debian-bootstrap.sh b/debian-bootstrap.sh
index c069dcb1..827e8460 100755
--- a/debian-bootstrap.sh
+++ b/debian-bootstrap.sh
@@ -18,6 +18,9 @@ apt-get install -y \
     build-essential \
     libncurses-dev \
     git \
+    wget \
+    m4 \
+    texlive-full \
     libgmp3c2 \
     libgmp3-dev \
     zlib1g-dev \
@@ -34,11 +37,11 @@ apt-get install -y \
     llvm \
     libbz2-dev \
     libjudy-dev \
+    libsqlite3-dev \
     libmysqlclient-dev \
     libpq-dev \
     libicu-dev \
     libssl-dev \
-    nettle-dev \
     libgsl0-dev \
     libblas-dev \
     liblapack-dev \
@@ -49,4 +52,20 @@ apt-get install -y \
     libyaml-dev \
     liblzma-dev \
     libsdl2-dev \
+    libxss-dev \
     libzmq3-dev
+
+mkdir /tmp/nettle-build
+(
+cd /tmp/nettle-build
+wget https://ftp.gnu.org/gnu/nettle/nettle-2.7.1.tar.gz
+tar zxf nettle-2.7.1.tar.gz
+cd nettle-2.7.1
+./configure --prefix=/usr
+make
+make install
+
+mkdir -p /usr/lib/x86_64-linux-gnu/
+ln -sfv /usr/lib/libnettle.so.4.7 /usr/lib/x86_64-linux-gnu/libnettle.so.4
+)
+rm -rf /tmp/nettle-build
diff --git a/stackage.cabal b/stackage.cabal
index 94b42da9..d12c172b 100644
--- a/stackage.cabal
+++ b/stackage.cabal
@@ -1,5 +1,5 @@
 name:                stackage
-version:             0.5.2
+version:             0.6.0.1
 synopsis:            "Stable Hackage," tools for creating a vetted set of packages from Hackage.
 description:         Please see <http://www.stackage.org/package/stackage> for a description and documentation.
 homepage:            https://github.com/fpco/stackage
@@ -23,6 +23,7 @@ library
                        Stackage.BuildPlan
                        Stackage.CheckBuildPlan
                        Stackage.UpdateBuildPlan
+                       Stackage.GhcPkg
                        Stackage.GithubPings
                        Stackage.InstallBuild
                        Stackage.PackageDescription
@@ -54,6 +55,7 @@ library
                      , yaml
                      , unix-compat
                      , http-client
+                     , http-conduit
                      , http-client-tls
                      , temporary
                      , data-default-class
@@ -63,6 +65,7 @@ library
                      , streaming-commons >= 0.1.7.1
                      , semigroups
                      , xml-conduit
+                     , conduit
 
 executable stackage
   default-language:    Haskell2010
@@ -72,6 +75,9 @@ executable stackage
                      , stackage
                      , optparse-applicative >= 0.11
                      , system-filepath
+                     , http-client
+                     , http-client-tls
+                     , text
   ghc-options:         -rtsopts -threaded -with-rtsopts=-N
 
 test-suite spec