Different handling of PL/pgSQL for-loop variables in 8.3.7 vs. 8.2.7 ???

We recently upgraded from postgres version 8.2.7 to 8.3.7. The below pl/pgsql test function behaves differently in the 2 versions.

The code of the function is :-

CREATE OR REPLACE FUNCTION "public"."testloop" () RETURNS varchar AS

$body$

BEGIN

    FOR idx IN 1..10 LOOP

        raise notice 'idx=%', idx;

        idx:=idx+1; 

    END LOOP;

    return '';

END;

$body$

LANGUAGE 'plpgsql'

The sql :-

select testloop();

in 8.2.7 returns:-

NOTICE:  idx=1

NOTICE:  idx=3

NOTICE:  idx=5

NOTICE:  idx=7

NOTICE:  idx=9

But in 8.3.7 returns:-

NOTICE:  idx=1

NOTICE:  idx=2

NOTICE:  idx=3

NOTICE:  idx=4

NOTICE:  idx=5

NOTICE:  idx=6

NOTICE:  idx=7

NOTICE:  idx=8

NOTICE:  idx=9

NOTICE:  idx=10

So in 8.3.7, the incrementing of the for-loop variable “idx” is being ignored; that is not the case in 8.2.7. Is this a new feature of 8.3.7 or a bug?

Since a lot of our functions depend on manual altering of for-loop variables, any prompt help/advise/suggestions would be greatly appreciated!