diff --git a/library/Potoki/Produce.hs b/library/Potoki/Produce.hs
--- a/library/Potoki/Produce.hs
+++ b/library/Potoki/Produce.hs
@@ -13,6 +13,8 @@
   directoryContents,
   finiteMVar,
   infiniteMVar,
+  tbmChan,
+  tmChan,
   enumInRange,
   mergeOrdering,
   unfoldr,
diff --git a/potoki.cabal b/potoki.cabal
--- a/potoki.cabal
+++ b/potoki.cabal
@@ -1,7 +1,7 @@
 name:
   potoki
 version:
-  2.1.3
+  2.1.4
 synopsis:
   Simple streaming in IO
 description:
@@ -73,5 +73,5 @@
     Potoki.Produce
     Potoki.Transform
   build-depends:
-    potoki-core >=2.3.3 && <2.4
+    potoki-core >=2.3.4 && <2.4