You may try to open a ticket with Intel Premier Support https://www.intel.com/content/www/us/en/programmable/quartushelp/current/index.htm#reference/glossar... to request for older version of Quartus.
I'm having a project source of old project which was generated with 15.1 in Cyclone 4 device. While running the TCL with latest version it shows error that "some of the functions are removed in the later version".
To verify the version related issue, I need 15.1
And may i know How to get premier support?
This was the link https://www.intel.com/content/www/us/en/my-intel/fpga-sign-in.html?redirect=/content/www/us/en/secur... . Or you may communicate directly with your Intel/Altera support representatives and open a support case.