You can download Hotfix #7 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 2.12.1
  Select hotfix-7

You should then be able to see and download the files.
TIB_substation_2.12.1_zos.sxs.hotfix_#7.zip
TIB_substation_2.12.1_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 #7:
 

SSES-2158 - High
  
Remove Mainframe HUB requirement when using the EXCI interface.
Records in CICS such as - SXG_SMF occur multiple times when the Mainframe HUB
is not present. The change eliminates the use for Mainframe HUB until v3.0
is used. CICS modules SXCOSRVA and SXCOSRVT have been changed for this hotfix. 
This has now been fixed.

Details of cumulative fixes previously published in Hotfixes 1 to 6 and included in Hotfix 7 are available in the readme.