In the paypal developer page they still state:
no_note Required Do not prompt buyers to include a note with their payments.
Allowable values for Subscribe buttons:
1 — hide the text box and the prompt
For Subscribe buttons, always set no_note to 1.
and
no_note Optional Do not prompt buyers to include a note with their payments.
Allowable values are:
0 — provide a text box and prompt for the note
1 — hide the text box and the prompt
The default is 0. To add a text label for the text box, such as,
Enter any special instructions:, use the cn variable.
But the following was deprecated:
cn Optional Related to the no_note variable. When no_note is 0, a text box is
displayed at checkout for buyers who would like to include any
special instructions. Use the cn field to enter a custom note or
label for this text box, such as, Enter any special instructions:
Hope that helps