I've shown 2 versions of tr operating below. Version 5 from
slackware 10. And version 2 from slackware 7. Version 2 of tr
appears to working as expected, but version 5 doesn't.
Version 5 behaves abnormally on other char classes as well.

# tr version 5.2.1 appears to behave abnormally.
# Delete all punct chars using tr version 5.2.1 from Slackware 10.0
# note that \260 and \250 are not punct chars, but are deleted.
/bin/echo -e '\260\250?' | tr -d '[unct:]' | xxd
0000000: 0a .

# Delete all non-punct chars using tr version 5.2.1 from Slackware 10.0
# Note that \260 and \250 are non punct chars and should be deleted, but
# are not. The newline is deleted correctly. 'b0' is \260, 'a8' is \250.
/bin/echo -e '\260\250?' | tr -dc '[unct:]' | xxd
0000000: b0a8 3f ..?

# tr version 2.0 appears to behave normally.
# Delete all punct chars using tr version 2.0 from Slackware 7
# This behaves normally (to me). Only the '?' is deleted.
/bin/echo -e '\260\250?' | tr -d '[unct:]' | xxd
0000000: b0a8 0a ...

# Delete all non-punct chars using tr version 2.0 from Slackware 7
# This behaves normally (to me). All but the '?' are deleted.
/bin/echo -e '\260\250?' | tr -dc '[unct:]' | xxd
0000000: 3f ?

Is the new tr ok?