As we already said in our previous coverage, this is not the 4th edition of the product but the 2nd.
VMware launched SRM 1.0 in June 2008, directly jumping to version 4.0 to explicit the support for vSphere 4.0.
Nonetheless the product is making a notable progress, supporting 12 vendors (a list of 11 is here) that offer fibre channel, iSCSI and NFS storage replication solutions, and supporting 3rd party virtual switches like the Cisco Nexus 1000V.
The most relevant new feature anyway is the support for Many-to-One Failover scenarios, where a single recovery site can receive virtual machines coming from multiple production sites.
Hopefully this is just the prelude to the Many-to-Many Failover that many customers are waiting for.
VMware published a nice walkthrough here.