So this version is the last version to support DX9, right?
Yep!
Where i can find more info about the ECS implementation? Is OpenGL in sync with DX11 features?
I'll start working on some wiki pages/tutorial bits, but the first thing you need to do if you want to start playing with it is activate it in cmake and compile it in.
You can do that by turning on the advanced flag TORQUE_EXPERIMENTAL_EC, generating and rebuilding. That'll build the engine stuffs with it included, and if you run the install project, it'll install the associated files/tool bits for the full template as well.
From there, when you go into a level, you can find the Entity class type to spawn it under the Level folder in the creator. If you select an entity, there'll be a drop-down that lists available components that can be added to the entity. Any components on the entity will be show up in a special sub-item in the Scene heirarchy tree called 'Components'. In there you can select the components, modify their properties, etc.
You can also save a Entity to be a 'game object', which is pretty much a prefab with an associated script, by right-clicking on an entity in the scene view and clicking the associated command. Any Game Objects will show up in the GameObjects folder in the scripted tab in the creator.
This way, you can build up, say, a player object(the included example GameObject is an example of how a player object for a third person game may be configured), save it as a Game Object with a unique name, and readily spawn it via the editor, or the console command spawnGameObject(%gameObjectName, %addToMissionGroup);
Once it's been created via the editor, it'll have a script generated alongside it you can add code to affect the game object as a whole, or modify/create new components for particular behavior.
As for the DX/GL, az answered that one above.