@JM1010101 in my experience if the line and load switches (first and last) are installed correctly it can work.  However, I did get a "switch is incorrectly wired" note and had to turn breaker off then back on and it worked.  The lights sometimes are delayed in responding but the two pairs that I've installed work with the app just fine.  

  @board4mic 

Is there any way to get dimming to work in this scenario, even if the app cant control it? 

 I've been DIY ing  for a long time with TP link products.  I just built a house and there are multiple locations with 4, and even 5 and 6 way.   I have drawn out the circuits checked things with volt meter and ohm meters to make sure everything is correct. However both sets I've installed so far failed. The 4 way switch does nothing.   If lights are on, flipping the 4 way flickers but stays on.  If lights are off nothing happens.  Pretty frustrating.  Customer service won't help because they don't support 4 or more way installation.  I'm using KS-230 kits.  All of my 3 way set ups and single poles work fine.  I need some (but not all) of the middle switches to work.  Any ideas anyone??   It seems like it would be easy to make and sell a pass thru switch that would transmit via wifi on and off????!!!!   

  @Chicago_SH 

i have this configuration and the 4 way dumb switch cant turn the light ON from an off position, can only turn the light off if its on?

  @Chicago_SH thanks I got this to work as well. I used  hs210 kit. i put the smart switch at each end. in the middle i put a standard fourway switch.p

  @judetf Can you explain exactly how you connected the satelite in the 4 way switch? There are 4 travelers in the 4 way switch (2 red 2 black). Satelites are also supposed to have the load wire connected and there is no load wire in a 4 way switch.

  @judetf, that is great info on the extra main switch. I will do the same with my leftover main.  Unfortunately my setup did not go as well as yours. I am wired the same way as you but am experiencing a few quirks.  My 1st satellite (inbound from main, outbound to second satellite on both traveler 1 & 2) works great .  On/Off is consistent and dimming works well.  But my second satellite is very intermittent.  On/off works some of the time and same for dimming.   Interestingly I find that if the load is dimmed slightly (or at all), the 2nd satellite works fine. If brightness is full then it has issues almost as if there is noise on the line and it can't hear/receive commands when on full brightness. 
 

Neither of the ring lights turn off/on with the load on the two satellites.  They stay lit all the time no matter the state of the light.  Works fine on the main. Are the ring lights on the satellites working correctly in your setup?

I got a 4-way setup to work using two KS230 v1 kits. The setup required one of the Main switches and both of the Sattelite switches. For my configuration, the Main got installed where line/power comes in. Traveler 1 and Traveler 2 went to the first Satellite. From there both Traveler wires were connected to the appropriate terminal in the Satellite, and the second set of Travelers wires were also connected, heading to the second Satellite. At the second satellite I connected both Traveler wires, and also connected my Load line to Traveler 2, and everything works.

While this required purchasing an extra KS230 kit, I'm going to use the spare Main switch as just a normal Kasa smart switch. I've tested it and with line/power connected, I can connect the load of another light to either Traveler terminal and it will control that light perfectly.

jtf