Best to continue using current/expired forms
You may have noticed that the U.S. Department of Labor FMLA forms have an expiration date of March 31, 2015. As with "best if used by" dates on many food products, that doesn't meant the documents are stale and unhealthy to use.
The DOL is in the process of gathering and reviewing comments for suggested revisions, a process undertaken every few years, but it's not clear when updated forms will be available. The wheels of government do move slowly.
It should be noted that while federal FMLA regulations mandate that employers provide employees certain notices (see U.S. Labor Department Fact Sheet # 28D: Employer Notification Requirements under the Family and Medical Leave Act) the mandate is a "performance" standard, specifying what information must be provided and when, but not dictating the actual format of the notice. As stated in the fact sheet, use of the DOL forms is discretionary: "Employers may use Form WH-xxx, which is available at no cost from the WHD website to provide this notice."
Consequently, employers could craft their own forms, as long as they contained the required information. Of course use of DOL- "recommended" forms is a safe harbor. After all, how could the DOL accuse an employer of violating the notice requirements if using the DOL's very own forms?
For now, employers may/should continue to use the old forms until updated versions are available. As posted on the DOL website, here is the list of recommended forms for downloading, still with the March 31, 2015 expiration date: