So I'm not nuts after all

It appears that at least in the Eastern triangle T is not upgradeable.
http://www.flyertalk.com/forum/Forum5/HTML/007994.html
quote:
--------------------------------------------------------------------------------
Originally posted by 100,000miler:
Question: These are not upgradeable fares, right?
--------------------------------------------------------------------------------
Right. L and T are not upgradeable.
quote:
Answered by
Empress