diff --git a/FollowingFileStream/AsyncStream.cs b/FollowingFileStream/AsyncStream.cs
index 391c811..dcb12c8 100644
--- a/FollowingFileStream/AsyncStream.cs
+++ b/FollowingFileStream/AsyncStream.cs
@@ -11,6 +11,7 @@ namespace Manandre.IO
     /// </summary>
     public abstract class AsyncStream : Stream
     {
+#if !NETSTANDARD1_3
         /// <summary>
         /// Begins an asynchronous read operation. (Consider using AsyncStream.ReadAsync(System.Byte[],System.Int32,System.Int32,System.Threading.CancellationToken)
         /// instead.)
@@ -131,6 +132,7 @@ public sealed override void EndWrite(IAsyncResult asyncResult)
         {
             ((Task)asyncResult).GetAwaiter().GetResult();
         }
+#endif
 
         /// <summary>
         /// Clears all buffers for this stream and causes
diff --git a/FollowingFileStream/FollowingFileStream.cs b/FollowingFileStream/FollowingFileStream.cs
index 3a3a7aa..027435f 100644
--- a/FollowingFileStream/FollowingFileStream.cs
+++ b/FollowingFileStream/FollowingFileStream.cs
@@ -294,8 +294,7 @@ private bool IsFileLockedForWriting()
             }
             finally
             {
-                if (stream != null)
-                    stream.Close();
+                stream?.Dispose();
             }
 
             //file is not locked
diff --git a/FollowingFileStream/FollowingFileStream.csproj b/FollowingFileStream/FollowingFileStream.csproj
index c4d5e25..51ed82b 100644
--- a/FollowingFileStream/FollowingFileStream.csproj
+++ b/FollowingFileStream/FollowingFileStream.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>Library</OutputType>
-    <TargetFramework>netcoreapp2.2</TargetFramework>
+    <TargetFrameworks>netstandard2.0;netstandard1.3</TargetFrameworks>
     <DocumentationFile>bin\$(Configuration)\$(TargetFramework)\$(AssemblyName).xml</DocumentationFile>
   </PropertyGroup>
   <PropertyGroup>