Tin-1.2 PL0 is still available as tin.old on the above architectures, in case you want to use it. (There is a new "feature" in tin-1.2 PL2 that I personally find annoying, dealing with different behavior during group/article selection by number. Now if you type a number to select a group or article and hit return, it enters the group or reads the article immediately, instead of just moving to the group or article.)
There's been a minor change made to the existing tin-1.2 PL2 on AIX; now it uses rcfnews.cs.umass.edu as its default server instead of kernighan.cs.umass.edu (same machine, currently, but might not always be that way).
Tin-1.2 PL2 will be installed for Solaris next week.