Take in mind that updates releases are different from patches releases, take a look here: VMware KB: Understanding ESXi 5.x Patching Model
Release Contents
Both patch and update releases have bulletins that can be used by the vSphere Update Manager users to patch the ESXi host. Patch and update releases also have VIB files and image profiles that can be used by the ESXCLI users to patch the ESXi host. Even though patch and update releases are structured in the same manner, they are different in the following aspects:
- An update release contains more bug fixes than a patch release.
- A patch release only contains high severity fixes whereas an update release contains high and low severity fixes and probably important features and hardware enablements.
- Update release has a rollup bulletin that contains the latest VIBs with all the fixes since the initial release of an ESXi release (ESXi 5.0, ESXi 5.1, or ESXi 5.5).
- Update release is delivered as an additional install ISO.
