diff --git a/nanoFramework.System.Net.Http.Client.nuspec b/nanoFramework.System.Net.Http.Client.nuspec
index 3f482bb..2ad32ac 100644
--- a/nanoFramework.System.Net.Http.Client.nuspec
+++ b/nanoFramework.System.Net.Http.Client.nuspec
@@ -22,7 +22,7 @@ There is also a package with the server API only and another with the full API.<
       <group targetFramework=".NETnanoFramework1.0">
         <dependency id="nanoFramework.CoreLibrary" version="2.0.0-preview.52" />
         <dependency id="nanoFramework.Runtime.Events" version="2.0.0-preview.13" />
-        <dependency id="nanoFramework.System.Collections" version="2.0.0-preview.14" />
+        <dependency id="nanoFramework.System.Collections" version="2.0.0-preview.15" />
         <dependency id="nanoFramework.System.Text" version="2.0.0-preview.18" />
         <dependency id="nanoFramework.System.Net" version="2.0.0-preview.23" />
         <dependency id="nanoFramework.System.Threading" version="2.0.0-preview.14" />
diff --git a/nanoFramework.System.Net.Http.Client/System.Net.Http.Client.nfproj b/nanoFramework.System.Net.Http.Client/System.Net.Http.Client.nfproj
index b31e784..62b56e1 100644
--- a/nanoFramework.System.Net.Http.Client/System.Net.Http.Client.nfproj
+++ b/nanoFramework.System.Net.Http.Client/System.Net.Http.Client.nfproj
@@ -216,7 +216,7 @@
       <HintPath>..\packages\nanoFramework.Runtime.Events.2.0.0-preview.13\lib\netnano1.0\nanoFramework.Runtime.Events.dll</HintPath>
     </Reference>
     <Reference Include="nanoFramework.System.Collections, Version=2.0.0.0, Culture=neutral, PublicKeyToken=c07d481e9758c731">
-      <HintPath>..\packages\nanoFramework.System.Collections.2.0.0-preview.14\lib\netnano1.0\nanoFramework.System.Collections.dll</HintPath>
+      <HintPath>..\packages\nanoFramework.System.Collections.2.0.0-preview.15\lib\netnano1.0\nanoFramework.System.Collections.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.18\lib\netnano1.0\nanoFramework.System.Text.dll</HintPath>
diff --git a/nanoFramework.System.Net.Http.Client/packages.config b/nanoFramework.System.Net.Http.Client/packages.config
index f5d75ef..0a69920 100644
--- a/nanoFramework.System.Net.Http.Client/packages.config
+++ b/nanoFramework.System.Net.Http.Client/packages.config
@@ -2,7 +2,7 @@
 <packages>
   <package id="nanoFramework.CoreLibrary" version="2.0.0-preview.52" targetFramework="netnano1.0" />
   <package id="nanoFramework.Runtime.Events" version="2.0.0-preview.13" targetFramework="netnano1.0" />
-  <package id="nanoFramework.System.Collections" version="2.0.0-preview.14" targetFramework="netnano1.0" />
+  <package id="nanoFramework.System.Collections" version="2.0.0-preview.15" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.IO.Streams" version="2.0.0-preview.21" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.Net" version="2.0.0-preview.23" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.Text" version="2.0.0-preview.18" targetFramework="netnano1.0" />
diff --git a/nanoFramework.System.Net.Http.Client/packages.lock.json b/nanoFramework.System.Net.Http.Client/packages.lock.json
index 340ce19..8cbe93d 100644
--- a/nanoFramework.System.Net.Http.Client/packages.lock.json
+++ b/nanoFramework.System.Net.Http.Client/packages.lock.json
@@ -16,9 +16,9 @@
       },
       "nanoFramework.System.Collections": {
         "type": "Direct",
-        "requested": "[2.0.0-preview.14, 2.0.0-preview.14]",
-        "resolved": "2.0.0-preview.14",
-        "contentHash": "bD/aprDzvUS7UGXXnP1NxY2fVw2686gNtiDXt1CV3IMA6YKu7cGXdPXfO8RYDkPNkHJ8omuHNuyUaq0OhJH82g=="
+        "requested": "[2.0.0-preview.15, 2.0.0-preview.15]",
+        "resolved": "2.0.0-preview.15",
+        "contentHash": "yyTSBujvtMHe5IYK26Q4Ys3o19pmrzhYDUzRHgnKFZNcQYRUIfd1C9Vt2UBDPF3hjHQnIVtrnry+7Pp/U00U/g=="
       },
       "nanoFramework.System.IO.Streams": {
         "type": "Direct",
diff --git a/nanoFramework.System.Net.Http.Server.nuspec b/nanoFramework.System.Net.Http.Server.nuspec
index c441c4d..5113cb4 100644
--- a/nanoFramework.System.Net.Http.Server.nuspec
+++ b/nanoFramework.System.Net.Http.Server.nuspec
@@ -22,7 +22,7 @@ There is also a package with the client API only and another with the full API.<
       <group targetFramework=".NETnanoFramework1.0">
         <dependency id="nanoFramework.CoreLibrary" version="2.0.0-preview.52" />
         <dependency id="nanoFramework.Runtime.Events" version="2.0.0-preview.13" />
-        <dependency id="nanoFramework.System.Collections" version="2.0.0-preview.14" />
+        <dependency id="nanoFramework.System.Collections" version="2.0.0-preview.15" />
         <dependency id="nanoFramework.System.Text" version="2.0.0-preview.18" />
         <dependency id="nanoFramework.System.Net" version="2.0.0-preview.23" />
         <dependency id="nanoFramework.System.Threading" version="2.0.0-preview.14" />
diff --git a/nanoFramework.System.Net.Http.Server/System.Net.Http.Server.nfproj b/nanoFramework.System.Net.Http.Server/System.Net.Http.Server.nfproj
index 1f47285..d7818f2 100644
--- a/nanoFramework.System.Net.Http.Server/System.Net.Http.Server.nfproj
+++ b/nanoFramework.System.Net.Http.Server/System.Net.Http.Server.nfproj
@@ -142,7 +142,7 @@
       <HintPath>..\packages\nanoFramework.Runtime.Events.2.0.0-preview.13\lib\netnano1.0\nanoFramework.Runtime.Events.dll</HintPath>
     </Reference>
     <Reference Include="nanoFramework.System.Collections, Version=2.0.0.0, Culture=neutral, PublicKeyToken=c07d481e9758c731">
-      <HintPath>..\packages\nanoFramework.System.Collections.2.0.0-preview.14\lib\netnano1.0\nanoFramework.System.Collections.dll</HintPath>
+      <HintPath>..\packages\nanoFramework.System.Collections.2.0.0-preview.15\lib\netnano1.0\nanoFramework.System.Collections.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.18\lib\netnano1.0\nanoFramework.System.Text.dll</HintPath>
diff --git a/nanoFramework.System.Net.Http.Server/packages.config b/nanoFramework.System.Net.Http.Server/packages.config
index f5d75ef..0a69920 100644
--- a/nanoFramework.System.Net.Http.Server/packages.config
+++ b/nanoFramework.System.Net.Http.Server/packages.config
@@ -2,7 +2,7 @@
 <packages>
   <package id="nanoFramework.CoreLibrary" version="2.0.0-preview.52" targetFramework="netnano1.0" />
   <package id="nanoFramework.Runtime.Events" version="2.0.0-preview.13" targetFramework="netnano1.0" />
-  <package id="nanoFramework.System.Collections" version="2.0.0-preview.14" targetFramework="netnano1.0" />
+  <package id="nanoFramework.System.Collections" version="2.0.0-preview.15" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.IO.Streams" version="2.0.0-preview.21" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.Net" version="2.0.0-preview.23" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.Text" version="2.0.0-preview.18" targetFramework="netnano1.0" />
diff --git a/nanoFramework.System.Net.Http.Server/packages.lock.json b/nanoFramework.System.Net.Http.Server/packages.lock.json
index 340ce19..8cbe93d 100644
--- a/nanoFramework.System.Net.Http.Server/packages.lock.json
+++ b/nanoFramework.System.Net.Http.Server/packages.lock.json
@@ -16,9 +16,9 @@
       },
       "nanoFramework.System.Collections": {
         "type": "Direct",
-        "requested": "[2.0.0-preview.14, 2.0.0-preview.14]",
-        "resolved": "2.0.0-preview.14",
-        "contentHash": "bD/aprDzvUS7UGXXnP1NxY2fVw2686gNtiDXt1CV3IMA6YKu7cGXdPXfO8RYDkPNkHJ8omuHNuyUaq0OhJH82g=="
+        "requested": "[2.0.0-preview.15, 2.0.0-preview.15]",
+        "resolved": "2.0.0-preview.15",
+        "contentHash": "yyTSBujvtMHe5IYK26Q4Ys3o19pmrzhYDUzRHgnKFZNcQYRUIfd1C9Vt2UBDPF3hjHQnIVtrnry+7Pp/U00U/g=="
       },
       "nanoFramework.System.IO.Streams": {
         "type": "Direct",
diff --git a/nanoFramework.System.Net.Http.nuspec b/nanoFramework.System.Net.Http.nuspec
index 30acf0c..24a92ff 100644
--- a/nanoFramework.System.Net.Http.nuspec
+++ b/nanoFramework.System.Net.Http.nuspec
@@ -22,7 +22,7 @@ These are meant to be used when there is the need to use smaller assemblies.</de
     <dependencies>
       <dependency id="nanoFramework.CoreLibrary" version="2.0.0-preview.52" />
       <dependency id="nanoFramework.Runtime.Events" version="2.0.0-preview.13" />
-      <dependency id="nanoFramework.System.Collections" version="2.0.0-preview.14" />
+      <dependency id="nanoFramework.System.Collections" version="2.0.0-preview.15" />
       <dependency id="nanoFramework.System.Text" version="2.0.0-preview.18" />
       <dependency id="nanoFramework.System.Net" version="2.0.0-preview.23" />
       <dependency id="nanoFramework.System.Threading" version="2.0.0-preview.14" />
diff --git a/nanoFramework.System.Net.Http/System.Net.Http.nfproj b/nanoFramework.System.Net.Http/System.Net.Http.nfproj
index 4f008e1..2582bf8 100644
--- a/nanoFramework.System.Net.Http/System.Net.Http.nfproj
+++ b/nanoFramework.System.Net.Http/System.Net.Http.nfproj
@@ -116,7 +116,7 @@
       <HintPath>..\packages\nanoFramework.Runtime.Events.2.0.0-preview.13\lib\netnano1.0\nanoFramework.Runtime.Events.dll</HintPath>
     </Reference>
     <Reference Include="nanoFramework.System.Collections, Version=2.0.0.0, Culture=neutral, PublicKeyToken=c07d481e9758c731">
-      <HintPath>..\packages\nanoFramework.System.Collections.2.0.0-preview.14\lib\netnano1.0\nanoFramework.System.Collections.dll</HintPath>
+      <HintPath>..\packages\nanoFramework.System.Collections.2.0.0-preview.15\lib\netnano1.0\nanoFramework.System.Collections.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.18\lib\netnano1.0\nanoFramework.System.Text.dll</HintPath>
diff --git a/nanoFramework.System.Net.Http/packages.config b/nanoFramework.System.Net.Http/packages.config
index f5d75ef..0a69920 100644
--- a/nanoFramework.System.Net.Http/packages.config
+++ b/nanoFramework.System.Net.Http/packages.config
@@ -2,7 +2,7 @@
 <packages>
   <package id="nanoFramework.CoreLibrary" version="2.0.0-preview.52" targetFramework="netnano1.0" />
   <package id="nanoFramework.Runtime.Events" version="2.0.0-preview.13" targetFramework="netnano1.0" />
-  <package id="nanoFramework.System.Collections" version="2.0.0-preview.14" targetFramework="netnano1.0" />
+  <package id="nanoFramework.System.Collections" version="2.0.0-preview.15" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.IO.Streams" version="2.0.0-preview.21" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.Net" version="2.0.0-preview.23" targetFramework="netnano1.0" />
   <package id="nanoFramework.System.Text" version="2.0.0-preview.18" targetFramework="netnano1.0" />
diff --git a/nanoFramework.System.Net.Http/packages.lock.json b/nanoFramework.System.Net.Http/packages.lock.json
index 340ce19..8cbe93d 100644
--- a/nanoFramework.System.Net.Http/packages.lock.json
+++ b/nanoFramework.System.Net.Http/packages.lock.json
@@ -16,9 +16,9 @@
       },
       "nanoFramework.System.Collections": {
         "type": "Direct",
-        "requested": "[2.0.0-preview.14, 2.0.0-preview.14]",
-        "resolved": "2.0.0-preview.14",
-        "contentHash": "bD/aprDzvUS7UGXXnP1NxY2fVw2686gNtiDXt1CV3IMA6YKu7cGXdPXfO8RYDkPNkHJ8omuHNuyUaq0OhJH82g=="
+        "requested": "[2.0.0-preview.15, 2.0.0-preview.15]",
+        "resolved": "2.0.0-preview.15",
+        "contentHash": "yyTSBujvtMHe5IYK26Q4Ys3o19pmrzhYDUzRHgnKFZNcQYRUIfd1C9Vt2UBDPF3hjHQnIVtrnry+7Pp/U00U/g=="
       },
       "nanoFramework.System.IO.Streams": {
         "type": "Direct",