VMware Build number Decoder Table
Ran across an EXCELLENT KB article in VMware’s Knowledge Base this week.
Correlating vCenter Server and ESXi/ESX host build numbers to update levels (1014508)
If you have been working with VMware for a while, you will be familiar with the way various patches and hotfixes increment the build numbers within the products. 
This document helps you correlate the various build versions back to the patches, updates and hotfixes installed. This is super useful since many of the KB articles and documentation refer to update levels and not build numbers for compatibility and prerequisites.
This Knowledge base doc covers all of VMware’s products. Although this document has been around since late 2011, I just ran across it recently. Definitely worth bookmarking.