diff --git a/app/Main.hs b/app/Main.hs
index 4d61daa..76fb6f2 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -10,14 +10,14 @@
 module Main where
 
 import qualified Control.Foldl as Foldl
-import           Control.Concurrent.Async (forConcurrently_)
+import           Control.Concurrent.Async (forConcurrently_, mapConcurrently)
 import qualified Data.Aeson as Aeson
 import           Data.Aeson.Types (fieldLabelModifier)
 import           Data.Aeson.Encode.Pretty
 import           Data.Foldable (fold, foldMap, traverse_)
 import qualified Data.Bifunctor as Bifunctor
 import qualified Data.Graph as G
-import           Data.List (maximumBy, nub)
+import           Data.List (maximumBy)
 import qualified Data.List as List
 import qualified Data.Map as Map
 import           Data.Maybe (fromMaybe, mapMaybe)
@@ -92,6 +92,7 @@ packageConfigToJSON =
                             , "depends"
                             ]
                , confIndent = Spaces 2
+               , confTrailingNewline = True
                }
 
 packageSetToJSON :: PackageSet -> Text
@@ -100,7 +101,11 @@ packageSetToJSON =
     . TB.toLazyText
     . encodePrettyToTextBuilder' config
   where
-    config = defConfig { confCompare = compare, confIndent = Spaces 2 }
+    config = defConfig
+               { confCompare = compare
+               , confIndent = Spaces 2
+               , confTrailingNewline = True
+               }
 
 writePackageFile :: PackageConfig -> IO ()
 writePackageFile =
@@ -188,7 +193,7 @@ performInstall set pkgName PackageInfo{ repo, version } = do
 
 getReverseDeps  :: PackageSet -> PackageName -> IO [(PackageName, PackageInfo)]
 getReverseDeps db dep =
-    nub <$> foldMap go (Map.toList db)
+    List.nub <$> foldMap go (Map.toList db)
   where
     go pair@(packageName, PackageInfo {dependencies}) =
       case List.find (== dep) dependencies of
@@ -270,7 +275,7 @@ install pkgName' = do
       echoT "Install complete"
     Just str -> do
       pkgName <- packageNameFromString str
-      let pkg' = pkg { depends = nub (pkgName : depends pkg) }
+      let pkg' = pkg { depends = List.nub (pkgName : depends pkg) }
       updateAndWritePackageFile pkg'
 
 uninstall :: String -> IO ()
@@ -469,17 +474,19 @@ verify arg = do
     verifyPackages names db pkg = do
       echoT $ "Verifying " <> pack (show $ length names) <> " packages."
       echoT "Warning: this could take some time!"
-
-      let go (name_, pkgInfo) = (name_, ) <$> performInstall (set pkg) name_ pkgInfo
-      paths <- Map.fromList <$> traverse go (Map.toList db)
-      traverse_ (verifyPackage db paths) names
-
-    verifyPackage :: PackageSet -> Map.Map PackageName Turtle.FilePath -> PackageName -> IO ()
-    verifyPackage db paths name = do
-      let dirFor pkgName = fromMaybe (error ("verifyPackageSet: no directory for " <> show pkgName)) (Map.lookup pkgName paths)
+      traverse_ (verifyPackage db pkg) names
+
+    verifyPackage :: PackageSet -> PackageConfig -> PackageName -> IO ()
+    verifyPackage db pkg name = do
+      let
+        dirFor pkgName =
+          case Map.lookup pkgName db of
+            Nothing -> error ("verifyPackageSet: no directory for " <> show pkgName)
+            Just pkgInfo -> performInstall (set pkg) pkgName pkgInfo
       echoT ("Verifying package " <> runPackageName name)
       dependencies <- map fst <$> getTransitiveDeps db [name]
-      let srcGlobs = map (pathToTextUnsafe . (</> ("src" </> "**" </> "*.purs")) . dirFor) dependencies
+      dirs <- mapConcurrently dirFor dependencies
+      let srcGlobs = map (pathToTextUnsafe . (</> ("src" </> "**" </> "*.purs"))) dirs
       procs "purs" ("compile" : srcGlobs) empty
 
 data BowerInfoRepo = BowerInfoRepo
@@ -522,9 +529,8 @@ addFromBower name = do
               )
       case result' of
         Right (pkgName, info) -> do
-          pkg <- readPackageFile
-          db <- readPackageSet pkg
-          writePackageSet pkg $ Map.insert pkgName info db
+          db <- readLocalPackageSet
+          writeLocalPackageSet $ Map.insert pkgName info db
           echoT $ "Successfully wrote " <> runPackageName pkgName <> " to package set."
         Left errors -> echoT $ "Errors processing Bower Info: " <> (T.pack errors)
   where
diff --git a/psc-package.cabal b/psc-package.cabal
index 89dd8bf..c736fd3 100644
--- a/psc-package.cabal
+++ b/psc-package.cabal
@@ -25,7 +25,7 @@ executable psc-package
                    process -any,
                    system-filepath -any,
                    text -any,
-                   turtle ==1.3.*
+                   turtle <1.6
     main-is: Main.hs
     other-modules: Paths_psc_package
                    Types
diff --git a/stack.yaml b/stack.yaml
index fc491c7..eabc584 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,4 +1,5 @@
-resolver: lts-8.15
+resolver: lts-11.1
 packages:
 - '.'
-extra-deps: []
+extra-deps:
+- aeson-pretty-0.8.5 # newer in lts-11.1 needed for formatting packages.json