All proposed 38 CFR changes must go through the Federal governmental process of posting a "Proposed Rule Change" on the daily published Federal Register (FR) and allowing time for comments to be received and evaluated by the VA (and also the VA checking the proposed changes against other administrative regulations/laws for consistency) BEFORE a "Final Rule" by VA is published in the FR which results in the changes being published in 38 CFR (pretty much the same governmental process typical for all changes to any CFRs, not just the 38 CFR VA one). This will typically take anywhere from 3 months to ? from the start of the publication date of the "Proposed Rule Change" in order to implement a CFR change. Until the "Final Rule" appears in the FR which outlines backdating requirements as well as implementation requirements, etc., VA will typically not process claims with consideration of any new ruling change announcements that may appear in the press.
You can keep yourself apprised of upcoming changes to 38 CFR by periodically checking the FR for new changes at http://www.gpoaccess.gov/fr/advanced.html. Use the "Search by Issue Date" option (use "after" from the last time you checked if you do this periodically) AND put "CFR Parts Affected in this Issue" (WITH the quote marks) in the Search Input box and then scanning the citations returned for any proposed changes to review them. That will give you a specific page number (the rightmost number in the line if you HTML view) to then go back to the Search box page to do a page number search on the FR, again using quote marks to surround the search term like the following example - "page xxxxx" where 'xxxxx' represents the page number . If only concerned about VA "rule" changes being proposed, those will be indicated as 38 CFR changes and often also be annotated as "Proposed Rules" (but not always).