@Extio 

We have been told by the development team that because of how the two KS230 switches communicate with each other, even with the 2nd switch being a non-wireless dummy switch, the KS230 is unable to be used in a 4 or 5-way environment. 

  @Carl 

Since the KS230s will not work, are there any Kasa dimmer switches/kit that will work in a 4-way configuration?

  @Extio I am curious about this too.. I would like to install more kasa products in my house but I need to find a solution for 3 dimmer locations (4 way setup) for some lights... let me know if you found out anything. Thanks!

  @Carl is it possible to use a ks230 main with multiple satellite switchs wired in parallel?

  @BonusCup 

The HS210 3-way switch can work but it is still outside the design of the product.  This FAQ may help.

  @Adelino1 

At this time we are being told by the design team that the KS230 can only be used in a 3-way enviroment.  Beyond the 2 switches prime and satalite(dummy) it would not work.  If that changes I will be happy to let the community know. 

  @Extio it works but it's expensive to do until TP-Link starts selling additional satellite switchs. Basically you will need to buy 2 ks230 kits for almost $100 for a 3 location light control. On the plus side you can dim from any of the three locations. I have it working in a 4 location setup. It's not officially supported so your milage may vary.