intervals in 7.3.1

Hi,

I have been using intervals in postgresql like this:

  select interval('2 weeks');

We upgraded to 7.3.1 and now this produces error:

  ERROR:  parser: parse error at or near "'2 weeks'" at character 17

this works ok:

  select '2 weeks'::interval;

this also:

  select date(current_timestamp);

Is this a bug or is installation gone terribly wrong or is it a new 
policy? Should I change all interval('xxx') to 'xxx'::interval?

-Jukka