If you are going to stop supporting Adobe XI and force us to go to Adobe DC Pro please at least make it to where we can re-arrange files in portfolios! This is a huge deal and we cant stay on older version because of security flaws but DC Pro has its limitations!
Sorry for the delay in response to your query and apologize for the inconvenience caused.
Please refer to the following links which discuss the similar issue How do I rearrange sections of a pdf portfolio?
For the End of support for Acrobat 11, you can refer to End of support for Adobe Acrobat XI and Reader XI Link: https://helpx.adobe.com/acrobat/kb/end-of-support-acrobat-xi-reader-xi.html
Hope this helps, and keep us posted with the results.