Upgrading from:

Utilities`Notation`

All the functionality of Utilities`Notation` is now available in the newly created Notation Package.

To access functionality from the new Notation Package, load Notation`:

Version 5.2 << Utilities`Notation`;
Notation[\!\(\*
TagBox[
RowBox[{
RowBox[{"x_", " ", 
SubscriptBox["\[CirclePlus]", "n_"], " ", "y_"}], " "}],
"NotationTemplateTag"]\) \[DoubleLongLeftRightArrow] \!\(\*
TagBox[
RowBox[{" ", 
RowBox[{"gplus", "[", 
RowBox[{"x_", ",", "y_", ",", "n_"}], "]"}]}],
"NotationTemplateTag"]\)];
\!\(a\ 
\*SubscriptBox[\(\[CirclePlus]\), \(n + m\)]\ b\) // FullForm