Tank Auth v1.0 (CI authentication library)

[eluser]imcl[/eluser]
I assume that if I have, say, 10 users registered and now I change from

Code:

$config['phpass_hash_portable'] = FALSE;

to

Code:

$config['phpass_hash_portable'] = TRUE;

this change will only apply to future users added to the database? In that case it would still not be portable.

So my question is: does the config change have an effect even on those passwords that were there before changing FALSE to TRUE, or do new passwords need to be generated after changing to TRUE?