diff --git a/System.IO.FileSystem.UnitTests/System.IO.FileSystem.UnitTests.nfproj b/System.IO.FileSystem.UnitTests/System.IO.FileSystem.UnitTests.nfproj
index c5b43ac..3dbecda 100644
--- a/System.IO.FileSystem.UnitTests/System.IO.FileSystem.UnitTests.nfproj
+++ b/System.IO.FileSystem.UnitTests/System.IO.FileSystem.UnitTests.nfproj
@@ -49,7 +49,7 @@
   </ItemGroup>
   <ItemGroup>
     <Reference Include="mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=c07d481e9758c731">
-      <HintPath>..\packages\nanoFramework.CoreLibrary.2.0.0-preview.35\lib\netnano1.0\mscorlib.dll</HintPath>
+      <HintPath>..\packages\nanoFramework.CoreLibrary.2.0.0-preview.39\lib\netnano1.0\mscorlib.dll</HintPath>
     </Reference>
     <Reference Include="nanoFramework.System.Text, Version=2.0.0.0, Culture=neutral, PublicKeyToken=c07d481e9758c731">
       <HintPath>..\packages\nanoFramework.System.Text.2.0.0-preview.8\lib\nanoFramework.System.Text.dll</HintPath>
diff --git a/System.IO.FileSystem.UnitTests/packages.config b/System.IO.FileSystem.UnitTests/packages.config
index 79c91a3..15f37b6 100644
--- a/System.IO.FileSystem.UnitTests/packages.config
+++ b/System.IO.FileSystem.UnitTests/packages.config
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="nanoFramework.CoreLibrary" version="2.0.0-preview.35" targetFramework="netnano1.0" />
+  <package id="nanoFramework.CoreLibrary" version="2.0.0-preview.39" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.IO.Streams" version="2.0.0-preview.10" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.Text" version="2.0.0-preview.8" targetFramework="netnano1.0" />
   <package id="nanoFramework.TestFramework" version="4.0.0-preview.47" targetFramework="netnano1.0" developmentDependency="true" />
diff --git a/System.IO.FileSystem.UnitTests/packages.lock.json b/System.IO.FileSystem.UnitTests/packages.lock.json
index 56a5458..97549a3 100644
--- a/System.IO.FileSystem.UnitTests/packages.lock.json
+++ b/System.IO.FileSystem.UnitTests/packages.lock.json
@@ -4,9 +4,9 @@
     ".NETnanoFramework,Version=v1.0": {
       "nanoFramework.CoreLibrary": {
         "type": "Direct",
-        "requested": "[2.0.0-preview.35, 2.0.0-preview.35]",
-        "resolved": "2.0.0-preview.35",
-        "contentHash": "l3LZs5zLeYKP+21DmVykOBWQvcLWOzgOls2JU6R2mRb2cz1+SitRCaEC5bTEJHs888JdHi3xWMVe3GkRzZ/2Lg=="
+        "requested": "[2.0.0-preview.39, 2.0.0-preview.39]",
+        "resolved": "2.0.0-preview.39",
+        "contentHash": "rkXOwaEq6GIm+dKZ7ICMrG23mln482vRXyDtaNfAeBpgGcgiuFJrbw7w0TTZ2DNhw1CUWlCWZZbXi6+/NHdpLg=="
       },
       "nanoFramework.System.IO.Streams": {
         "type": "Direct",
diff --git a/System.IO.FileSystem/System.IO.FileSystem.nfproj b/System.IO.FileSystem/System.IO.FileSystem.nfproj
index 029494a..47408ec 100644
--- a/System.IO.FileSystem/System.IO.FileSystem.nfproj
+++ b/System.IO.FileSystem/System.IO.FileSystem.nfproj
@@ -77,7 +77,7 @@
   </ItemGroup>
   <ItemGroup>
     <Reference Include="mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=c07d481e9758c731">
-      <HintPath>..\packages\nanoFramework.CoreLibrary.2.0.0-preview.35\lib\netnano1.0\mscorlib.dll</HintPath>
+      <HintPath>..\packages\nanoFramework.CoreLibrary.2.0.0-preview.39\lib\netnano1.0\mscorlib.dll</HintPath>
     </Reference>
     <Reference Include="nanoFramework.Runtime.Events, Version=2.0.0.0, Culture=neutral, PublicKeyToken=c07d481e9758c731">
       <HintPath>..\packages\nanoFramework.Runtime.Events.2.0.0-preview.8\lib\nanoFramework.Runtime.Events.dll</HintPath>
diff --git a/System.IO.FileSystem/packages.config b/System.IO.FileSystem/packages.config
index c49fe55..0294707 100644
--- a/System.IO.FileSystem/packages.config
+++ b/System.IO.FileSystem/packages.config
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="nanoFramework.CoreLibrary" version="2.0.0-preview.35" targetFramework="netnano1.0" />
+  <package id="nanoFramework.CoreLibrary" version="2.0.0-preview.39" targetFramework="netnano1.0" />
   <package id="nanoFramework.Runtime.Events" version="2.0.0-preview.8" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.IO.Streams" version="2.0.0-preview.10" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.Text" version="2.0.0-preview.8" targetFramework="netnano1.0" />
diff --git a/System.IO.FileSystem/packages.lock.json b/System.IO.FileSystem/packages.lock.json
index febedd3..bd4f78f 100644
--- a/System.IO.FileSystem/packages.lock.json
+++ b/System.IO.FileSystem/packages.lock.json
@@ -4,9 +4,9 @@
     ".NETnanoFramework,Version=v1.0": {
       "nanoFramework.CoreLibrary": {
         "type": "Direct",
-        "requested": "[2.0.0-preview.35, 2.0.0-preview.35]",
-        "resolved": "2.0.0-preview.35",
-        "contentHash": "l3LZs5zLeYKP+21DmVykOBWQvcLWOzgOls2JU6R2mRb2cz1+SitRCaEC5bTEJHs888JdHi3xWMVe3GkRzZ/2Lg=="
+        "requested": "[2.0.0-preview.39, 2.0.0-preview.39]",
+        "resolved": "2.0.0-preview.39",
+        "contentHash": "rkXOwaEq6GIm+dKZ7ICMrG23mln482vRXyDtaNfAeBpgGcgiuFJrbw7w0TTZ2DNhw1CUWlCWZZbXi6+/NHdpLg=="
       },
       "nanoFramework.Runtime.Events": {
         "type": "Direct",
diff --git a/nanoFramework.System.IO.FileSystem.nuspec b/nanoFramework.System.IO.FileSystem.nuspec
index 9647e88..873aef3 100644
--- a/nanoFramework.System.IO.FileSystem.nuspec
+++ b/nanoFramework.System.IO.FileSystem.nuspec
@@ -20,7 +20,7 @@ This package requires a target with System.IO.FileSystem v$nativeVersion$ (check
     <tags>nanoFramework C# csharp netmf netnf System.IO.FileSystem</tags>
     <dependencies>
       <group targetFramework=".NETnanoFramework1.0">
-        <dependency id="nanoFramework.CoreLibrary" version="2.0.0-preview.35" />
+        <dependency id="nanoFramework.CoreLibrary" version="2.0.0-preview.39" />
         <dependency id="nanoFramework.Runtime.Events" version="2.0.0-preview.8" />
         <dependency id="nanoFramework.System.IO.Streams" version="2.0.0-preview.10" />
         <dependency id="nanoFramework.System.Text" version="2.0.0-preview.8" />