Curtis,
You're absolutely right with finding conflicting recommendation in our docs. Some docs get stale, while other resources are updated a little more frequently. Here's my general advice (Going to be a winded response, so bare with me). My goal is to help you understand our approach so you can make better informed decisions.
Cisco will always recommend that you try to stay within a Long Lived Release (LLR) as much as possible. Here's some general guidelines with ACI LLRs:
- Two LLRs will be maintained at all times (currently this is 3.2 and 4.2, later in the year 5.2 will replace 3.2)
- Maintenance & Patches will primarily be focused on LLR
- LLRs are typically maintained for ~18 months
- Direct Upgrades between LLRs will always be supported (ie. 2.2 >> 3.2, 2.2 >> 4.2 etc)
Major versions are where you'd typically see new features released. Ex. 4.0, 4.1, 4.2, 5.0, 5.1 etc.
Within Major release then we have Maintenance Releases (MRs). These are typically released quarterly. Ex. 4.2(2), 4.2(3)...4.2(7) etc. MRs typically include a collection of fixes, feature enhancements, and sometimes additional HW support.
Finally, there are patch releases which only contain a handful of critical fixes these are designated by the letters. Ex. 4.2(6h), 4.2(6i) etc.
My personal advice is to stay within a LLR, and then at the 2nd last available MR, and latest patch release. The reason I'm advising to stay one MR behind is just to allow more adoption of the MR before implementing it. (Give it time to be generally tried & tested)
Keeping this in mind take this fictitious example. Imagine [only] these releases were available on CCO:
4.2(1a)
4.2(3a)
4.2(3b)
4.2(4)i
5.1(1d)
From here, I'd be recommending 4.2(3b). This is within the 4.2 LLR, and one MR behind the latest. finally it's the latest patch release of that MR. Patch release are always safe to be on the latest as they only include fixes and never new features.
So regardless what CCO puts a shiny star against as "Recommended" or what our docs might list, you'd be safe to make a decision based on above.
Hope this helps,
Robert
