# Updating to Arbor 3.9

Please note when updating from “Arbor 3.8.x” or earlier to “3.9.0” or later.
Check the following sections.

## Raised the minimum Unity version to 2019.4

The Unity working version of Arbor has been raised to Unity2019.4.
If you want to use Arbor 3.9.0 or later for Unity2018 or earlier projects, you will also need to update Unity.

## Rename all node types

You can now rename it regardless of the node type.
Along with that, the title bar of the behavior will also be displayed on the calculator node.

## ParameterContainer parameter addition menu

Changed to be displayed in the format of Behaviour Select Window. Along with that, we are grouping by type.

For more information, see ParameterContainer.

## Add Component menu

Changed the path of the Add Component menu for the following built-in components.

Component | Menu path
--- | ---
AgentController | Arbor > Navigation > AgentController
Waypoint | Arbor > Navigation > Waypoint

## Renaming components

### StateBehaviour

Old name | New name
--- | ---
AgentFollow | AgentMoveToTransform
AgentEscape | AgentEscapeFromTransform
LoadLevel | LoadScene
UnloadLevel | UnloadScene

## Renaming codes

Old name | New name
--- | ---
AgentController.Follow method | MoveTo

## Obsolete code

Obsolete code | Description
--- | ---
Arbor.BehaviourTree.TreeNodeBase.HasChildLinkSlot() | Changed to check with the implementation of IChildLinkSlotHolder
Arbor.BehaviourTree.TreeNodeBase.HasParentLinkSlot() | Changed to check with the implementation of IParentLinkSlotHolder