5.1 is a long-term release and 5.3 the short-term release version.
ePO is used in a wide variety of organisations. Where one organisation needs stability and a long support cycle, the other organisation attaches more value to faster updates containing the latest security features. Therefore, McAfee decided to start working with long-term and short-term releases for ePO.
Short-term ePO releases are supported until the next version is available. From that moment on, no more patches will be released for that version. Patches will be released for long-term ePO releases when necessary, even if newer versions are available.
ePO 5.0 is a short-term release which was replaced by the long-term release of ePO 5.1 in Q4 of 2013
The Support Lifecycle page ( McAfee Product and Technology Support Lifecycle - Software & Utilities | McAfee Support ) actually describes both 5.1 and 5.3 as "Long Term Support" releases with the same End-of-Life date of 31 Dec 2017 for both. I've also seen a KB article reference to a forthcoming 5.4 release (KB82675). It is not very clear what the EPO release strategy is at this point in regard to "long-term" vs "short-term" releases.
I wrestled with the same decision as you. I had just built a clean 5.1.1 server to start migrating nodes from our production 4.6.9 box. 5.3 was then released and I decided to upgrade to 5.3 based on the Lifecycle page listing it as LTS, I was doing a clean install, and the fact that I didn't know when 5.1.2 was going to be released. As it turned out, 5.1.2 was released 2 days after I upgraded to 5.3. So far, no regrets going to 5.3. And yes, it would be nice to have some documentation showing the differences between 5.1x and 5.3.
Thanks for the information. I am going to call McAfee Business support to see if they can explain the differences between 5.12 and 5.30.
Let us know what you find out, as I am curious as well.
Called Support this morning. Was told that the only major difference between 5.12 and 5.30 is with extensions. If you delete a product extension, you can save the policy and task information in case you decide to reinstall the extension later. This was added per customer requests. ePO 5.12 does not have that ability but everything else is the same. Both are long term release support versions. Since this is the only major difference, I may just update to ePO 5.12 for some added features and bug fixes.