diff --git a/build.gradle b/build.gradle
index 6f81a3a9..d92fcc74 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,5 +1,5 @@
 plugins {
-    id "org.jetbrains.kotlin.jvm" version "1.1.50" apply false
+    id "org.jetbrains.kotlin.jvm" version "1.1.51" apply false
 }
 
 allprojects{
diff --git a/numass-main/src/main/groovy/inr/numass/scripts/underflow/UnderflowUtils.groovy b/numass-main/src/main/groovy/inr/numass/scripts/underflow/UnderflowUtils.groovy
index 8e3415be..f385c25d 100644
--- a/numass-main/src/main/groovy/inr/numass/scripts/underflow/UnderflowUtils.groovy
+++ b/numass-main/src/main/groovy/inr/numass/scripts/underflow/UnderflowUtils.groovy
@@ -4,7 +4,7 @@ import hep.dataforge.cache.CachePlugin
 import hep.dataforge.data.DataNode
 import hep.dataforge.data.DataSet
 import hep.dataforge.grind.GrindShell
-import hep.dataforge.grind.workspace.GrindPipe
+import hep.dataforge.grind.actions.GrindPipe
 import hep.dataforge.meta.Meta
 import hep.dataforge.storage.commons.StorageUtils
 import hep.dataforge.tables.Table