Please advise the place where old versions of TTU might be downloaded. download.teradata.com contains only 16.05 and higher versions at the moment. TPT 15.10 for linux is a point of interest.
Prior versions of software can be downloaded via Teradata Access Portal "Update Your Software" link if you are authorized for "Teradata At Your Service" account.
Or contact your Teradata account representative for assistance.
I would like to add that TPT 15.10 is not a supported release anymore.
Thus, I question why you would want to download it.
I have TDExpress15.10SLES11 40G linux image (not in default setup, i am using it for some POC stuff) or 14.10 (initial setup). If you really need it for some version specific testing/analysis(like me :) , i can share it. Drop me a message.
But i think 16.xx is much better. There were several fixes and enhancement since 15.xx.