It is always the best to have all updates installed. So, you will have the best guaranty that all available fixes are installed or that you will have access to all new features for that version. But what for updates are available for which version of AutoCAD Plant 3D? Note that you have to install plain AutoCAD Updates separately. They are not included anymore in AutoCAD Plant 3D updates since some years.
Blog "What version is it anyway?"
One more note about the updates. While the plain AutoCAD updates are cumulative, the Plant updates aren't. This means that for plain AutoCAD it is already enough to install the latest update only but for Plant updates you have to install the former updates of the specific version before. Thumb rule for Plant updates: Install the updates in the order of the publish date (oldest one first).
So, here is the list:
AutoCAD Plant 3D 2016:
- AutoCAD Plant 3D: Extension 1 SP2
- Update Path: Extension 1 > SP2
- AutoCAD: SP1
AutoCAD Plant 3D 2017:
- AutoCAD Plant 3D: Update 2017.1.1
- Update Path: 2017.1 > 2017.1.1
- AutoCAD: Update 2017.1.2
AutoCAD Plant 3D 2018:
- AutoCAD Plant 3D: Update 2018.1.2
- Update Path: 2018.1.1 > 2018.1.2
- AutoCAD: Update 2018.1.2
AutoCAD Plant 3D 2019:
- AutoCAD Plant 3D: Update 2019.1
- AutoCAD: Update 2019.1.2
AutoCAD Plant 3D 2020:
- AutoCAD Plant 3D: Update 2020.0.1
- AutoCAD: Currently none
You can either get the updates via your Autodesk Account, section "Product Updates". Alternatively, if you have a desktop subscription, you can use the Autodesk Desktop App to be up to date with your updates.