Millions of taxpayers are finding out in letters the Canada Revenue Agency is no longer mailing out the traditional income-tax package, a move that's especially angered advocates for seniors.

Taxpayers who want to file their returns the old-fashioned way can download forms from a website or pick up their package at Canada Post.

"This is outrageous -- how are we just hearing about it now?" said Susan Eng of the Canadian Association of Retired Persons (CARP). "If you fail to file, you get a penalty. This is a pretty important change for people."

The CRA says 35% of taxpayers still file their taxes using paper forms, but about 1.3 million of the printed tax and benefits packages went unused last year.

"It costs about four times more to process a paper return than an electronic return," CRA spokesperson Philippe Brideau said an email.

Also discontinued this year is the Telefile phone service, which about 10% of taxpayers used.

Letters showing up in mailboxes now from the CRA say it will no longer automatically mail out the T1 pckages.

Eng called the move "manifestly unfair and, frankly, unnecessary," saying it's been "badly handled" and "follows a trend of pushing everyone online before they're ready."

She said CARP will write an official protest letter to the CRA.