diff --git a/exe/Main.hs b/exe/Main.hs
--- a/exe/Main.hs
+++ b/exe/Main.hs
@@ -13,6 +13,7 @@
 import           Data.List.NonEmpty  (NonEmpty ((:|)), toList)
 import           Data.Map.Strict     (Map)
 import qualified Data.Map.Strict     as Map
+import qualified Data.Set            as Set
 import           Data.Maybe          (maybeToList)
 import           Data.Text           (Text, intercalate, map, pack)
 import           Data.Text.IO        (putStrLn)
@@ -125,8 +126,9 @@
     roots :: [Reference]
     roots = fst <$> filter (\ (_, Span{..}) -> null references) ss
     orphans :: [Reference]
-    orphans = do absent <- (Map.keys children) \\ (Map.keys spans)
-                 concat $ maybeToList $ Map.lookup absent children
+    orphans = Set.foldl' f [] absentees
+      where absentees  = Map.keysSet children `Set.difference` Map.keysSet spans
+            f os absent = maybe os (os ++) $ Map.lookup absent children
     spans :: Map Reference Span
     spans = Map.fromList ss
     children :: Map Reference [Reference]
diff --git a/jaeger-flamegraph.cabal b/jaeger-flamegraph.cabal
--- a/jaeger-flamegraph.cabal
+++ b/jaeger-flamegraph.cabal
@@ -1,6 +1,6 @@
 cabal-version:       2.2
 name:                jaeger-flamegraph
-version:             1.3.0
+version:             1.3.1
 synopsis:            Generate flamegraphs from Jaeger .json dumps.
 license:             BSD-3-Clause
 license-file:        LICENSE
@@ -36,7 +36,7 @@
   ghc-options:        -Wall
                       -Werror=missing-home-modules
   build-depends:    , aeson                ^>= 1.4.1.0
-                    , containers           ^>= 0.6.0.1
+                    , containers           ^>= 0.6.0.1 || ^>= 0.5.11.0
                     , text                 ^>= 1.2.3.1
   default-language:   Haskell2010
 
@@ -55,7 +55,7 @@
   hs-source-dirs:     library
   exposed-modules:    Jaeger.Interval
                     , Jaeger.Data
-  build-depends:    , QuickCheck ^>= 2.12.6.1
+  build-depends:    , QuickCheck ^>= 2.11.3 || ^>= 2.12.6.1
 
 test-suite            tests
   import:             deps