Hi @msevestre,
There are distinct differences between the single tracker and dual tracker hardware versions, and this will have direct impact onto which ESS features they each support.
They are not the same in this respect.
Neither model should be considered equivalent to MultiPlus-II in regards to ESS support. It is all quite different, and specific for each model.
Some ESS features were added in to the Multi RS single tracker model, specifically the ability to stay connected to a grid connection without charging, changing modes to keep batteries charged, and to support an AC input connection to power loads when required, or based on certain state of charge.
Other features will not be added to the single tracker model in the future, specifically the ability to export, and maybe others.
This has been a challenge to document clearly, so my apologies for that. I will prepare something more definitive as a reference guide to clarify the situation officially but that will take a bit more time.
Until now please only buy hardware that is suitable in its current feature set for your application. DO NOT buy Victron equipment based on the prospect of future features becoming available, it will only lead to possible disappointment.