Encoding method used for the SSO saml request/data in the our application got depreciated

Question

We are using UTF8 encoding method to encode the SSO saml request/data in the our application and it was working fine. But suddenly the SSO functionality stopped working and on analysis we found that the encoding method used got depreciated.

Previous code which stopped working:

new DeflaterOutputStream(output)

Updated code which fixed the issue:

new DeflaterOutputStream(output, 
    new ICSharpCode.SharpZipLib.Zip.Compression.Deflater(
     level: ICSharpCode.SharpZipLib.Zip.Compression.Deflater.DEFAULT_COMPRESSION,
     noZlibHeaderOrFooter: true)))

So basically we had updated the DeflaterOutputStream to use DEFLATE and suppressed the header and footer to fix the issue.

Can some one tell when the old DeflaterOutputStream code got depreciated. We need to understand why the previous working code stopped working suddenly.

Thanks for all you help.