Update README.md

removed hints for legacy frameworks #110

Author: FreeAndNil

README.md

@@ -22,25 +22,15 @@ mailing list and discuss bigger changes before working on them.
 For bigger changes we must ask you to sign a Contributor License
 Agreement http://www.apache.org/licenses/#clas.
 
-Github pull requests are one way to contribute, The Apache issue
+Github pull requests are one way to contribute, the Apache issue
 tracker is no longer accepting new issues but is available at 
 https://issues.apache.org/jira/browse/LOG4NET for access to 
 previous issues. 
 
 Developing
 ==========
 
-log4net targets a wide array of .net platforms, including some
-which are out of support from Microsoft, making it difficult to
-install relevant SDKs and build for those targets. In particular,
-older Client Profile .NET Framework targets and dotnet core 1.1
-may be installed by using the bundled helper scripts:
-
-- [install-net-framework-sdk-3.5.ps1](install-net-framework-sdk-3.5.ps1)
-- [install-dotnet-core-sdk-1.1.ps1](install-dotnet-core-sdk-1.1.ps1)
-
-These scripts download the relevant installers from Microsoft servers,
-but you run them at your own risk.
+log4net targets net462 and netstandard2.0. 
 
 Please see 
 - [CONTRIBUTING.md](doc/CONTRIBUTING.md)