There is now a new DS-230 form:

Old one has an expiry date of 07/31/07 - new version has an expiry date of 09/30/2010

New I-864:

Old one has an expiry date of 10/31/07 - new version has an expiry date of 10/31/10

So if you have had your SO sign a DS-230 in advance or you have already filled out your I-864 ready to send, you will have to fill out new ones.

natashenika mentioned here that her lawyer has asked her to send him the newer version

Nothing has changed. You can still use the old one. NVC and Dept. of State will continue to accept both versions.

OMB has to reapprove every form at least every three years, and that's all the date change means. Only when the new version marks previous editions obsolete must the new form be used.

I stand corrected in one very important fact --- D.O.S. did mark the new form with previous editions obsolete.

While I'm not convinced the reviewers at NVC will be rejecting forms with the old date, it might be wise to make sure page 1 and page 3 are reprinted with the new date before submitting so everything is in the most proper ...

For Form I-864, however, per USCIS, the 10/18/07 and 11/01/06 editions can be used, but no other edition accepted.

If you download the I-864 from their site it has an expiry date of 10/31/10. Perhaps they just forgot to update the 'editions' blurb.

No, the 10/18/07 edition is the latest approved edition, the approval of which is valid until 10/31/2010. The dates mentioned are the edition release dates, not the OMB expire dates. I-864 was substantially redesigned in 2006 (including removing notarized signature, etc.), hence the reason prior editions not accepted.