You can download Hotfix #1 from the TIBCO Support Customer Portal Web UI (https://support.tibco.com).
Log in using your username and password for the TIBCO Support Web page. 

  Select Download
  Select Hotfixes
  Select AvailableDownloads
  Select Mainframe
  Select Substation
  Select 2.13.0
  Select hotfix-1

You should then be able to see and download the files.

TIB_substation_2.13.0_zos.sxs.hotfix_#1.zip

TIB_substation_2.13.0_readme_hotfix.txt

Please note: Non-DFSMSdss installation packages are available by request only.

Listed below is a summary of updates included. Please refer to the associated readme document for any additional information.

Closed issues in Hotfix #1:

  SSES-1922 - IMS Critical      

  Substation ES issue where a DPL process abends. The Recipe service has
  a MOR of 0 which is not handled correctly when an error condition has
  been detected.
 
  SSES-1913 - ESB Critical      

  Fixed Substation ES issue that truncates Correlation ID on response messages
  to 63 characters. We support the Correlation ID up to 4K in length.
  Substation ES internally will still only use the first 63 characters for
  reporting purposes.