backquote has been renamed to quasiquote, and the backquote character, ` , now reads as quasiquote. The semantics of nested quasiquote have changed to conform with the 3̊rs. This change should not cause you problems. If you need a more thorough explanation of this change, contact the implementors.
quasiquote now works on vectors. Thus,
| formula vobeyspaces : |
#(1 2 3)