diff --git a/core/src/main/scala/sbt/librarymanagement/RichUpdateReport.scala b/core/src/main/scala/sbt/librarymanagement/RichUpdateReport.scala
index 297611b64..39c4cd8f8 100644
--- a/core/src/main/scala/sbt/librarymanagement/RichUpdateReport.scala
+++ b/core/src/main/scala/sbt/librarymanagement/RichUpdateReport.scala
@@ -2,6 +2,7 @@ package sbt
 package librarymanagement
 
 import java.io.File
+import sbt.io.Milli.getModifiedTime
 
 /**
  * Provides extra methods for filtering the contents of an `UpdateReport`
@@ -10,7 +11,7 @@ import java.io.File
 final class RichUpdateReport(report: UpdateReport) {
   private[sbt] def recomputeStamps(): UpdateReport = {
     val files = report.cachedDescriptor +: allFiles
-    val stamps = files.map(f => (f, f.lastModified)).toMap
+    val stamps = files.map(f => (f, getModifiedTime(f))).toMap
     UpdateReport(report.cachedDescriptor, report.configurations, report.stats, stamps)
   }
 
diff --git a/ivy/src/main/scala/sbt/internal/librarymanagement/ivyint/GigahorseUrlHandler.scala b/ivy/src/main/scala/sbt/internal/librarymanagement/ivyint/GigahorseUrlHandler.scala
index a1109dc91..a2b4cb7a2 100644
--- a/ivy/src/main/scala/sbt/internal/librarymanagement/ivyint/GigahorseUrlHandler.scala
+++ b/ivy/src/main/scala/sbt/internal/librarymanagement/ivyint/GigahorseUrlHandler.scala
@@ -16,6 +16,7 @@ import org.apache.ivy.util.{ CopyProgressEvent, CopyProgressListener, Message }
 import org.apache.ivy.util.url.{ AbstractURLHandler, BasicURLHandler, IvyAuthenticator, URLHandler }
 import org.apache.ivy.util.url.URLHandler._
 import sbt.io.IO
+import sbt.io.Milli.setModifiedTime
 
 // Copied from Ivy's BasicURLHandler.
 class GigahorseUrlHandler extends AbstractURLHandler {
@@ -149,7 +150,7 @@ class GigahorseUrlHandler extends AbstractURLHandler {
 
       val lastModified = lastModifiedTimestamp(response)
       if (lastModified > 0) {
-        dest.setLastModified(lastModified)
+        setModifiedTime(dest, lastModified)
       }
 
       if (l != null) {
diff --git a/project/Util.scala b/project/Util.scala
index 5dacc7df8..2ef855762 100644
--- a/project/Util.scala
+++ b/project/Util.scala
@@ -26,6 +26,8 @@ object Util {
     val timestamp = formatter.format(new Date)
     val content = versionLine(version) + "\ntimestamp=" + timestamp
     val f = dir / "xsbt.version.properties"
+    // TODO: replace lastModified() with sbt.io.Milli.getModifiedTime(), once the build
+    // has been upgraded to a version of sbt that includes sbt.io.Milli.
     if (!f.exists || f.lastModified < lastCompilationTime(analysis) || !containsVersion(f, version)) {
       s.log.info("Writing version information to " + f + " :\n" + content)
       IO.write(f, content)