@ScottMan can you please explain a little more in detail. My electrician and I are trying to understand it. Are you saying we need two dumb/sattelite (only 2 screws) switches and one master (3screws)? Are we to replace the the 4way with a dumb/satellite switch. If so, please explain a little more in detail. Thank you for your help and fguring this out. TP-Link should really fill this void out.

  @Mopy, that's right. Put the master in the box where your line comes in. The first satellite will have two wires connected to each screw - one being the traveler from the master and the other being the traveler to satellite #2. That is the case for both traveler #1 and #2. The second satellite has the load connected to the same screw as traveler #2 just like a normal KS230 3-way configuration. Hope this is clear.

I agree that tp-link should be addressing this. This configuration has been working great for me for about a month now - so I'm hopeful that it will be stable for years to come. I'm not sure if you can add more switches in line like this - like a normal 4-way switch where you can add as many as you want. I suspect that adding more will become problematic for the internal circuitry (as the switches are operating in parallel) and that is the reason that tp-link does not want to support this as a true 4-way switch. 

  @ScottMan thank you for your quick reply. I got it working. Everything works as should via APP and via switch. I simply bypassed the 4 way switch by wirenut traveler 1 together and traveler 2 together and went master Switch to the satellite #1 and put traveler 2 and load together  And traveler 1 on it own screw. (Like normal instructions) Then turned off breaker and undid the bypass I did and plugged in satellite 2 the same way as satellite #1. In parallel. I think your right and traveler 1 might be used as communication. My big confusion with your explanation was you mention you installed the them in serial. I got it working before I saw your post as I didn't think you would respond so fast. 

Anyway! Thank for your help! I wouldn't have been able to do it without your initial post.

P.s. I suspect it might work for 4 total switches with 1 master and 3 satellites. Haven't tried it but I'm curious what the satellite limit would be.

I plan to only replace the line-side 3-way switch with a smart 3-way switch, and leave the load-side 3-way and 4-way switches dumb.  However they both share gangs with other smart kasa switches, so I want them to match aesthetically. Does tp-link make dumb 3-way or 4-way switch replacements that match...at least somewhat?

  @ScottMan I am trying to install KS230's in a 4-way set up but haven't quite been able to figure this out.   Any additional help would be greatly appreciated.  I have a house full of Kasa switches that I installed myself so I have had plenty of experience with their products but this one has me stumped.  Here is more info on my configuration and for reference I am using the v2 version of the switches but it sound like you may have the original version.
 

My line and load are in the first box and so I used that as my master.  2nd switch is where the 4-way switch was located so I installed a satellite there.  Also a satellite at the 3rd switch.  My switch to switch wire is a 14/3+ground (black, white, red, copper).  At the master I am using red and white as travelers (red bottom, white top), black is connected to the load (coming back from the load out out on the satellite switches).  And then of course the master's line and neutral are connected as well.

Satellite #1 is the mid point so it has 2 reds on the bottom traveler connection and 2 whites on top traveler connection, black load is connected to the two black wires.

Satellite #2 is where I get confused.  Could you share some additional insight on what you connected to get this working?  In step 4 when you say load connected to traveler 2, do you mean to connect it to the load wire on the back of the switch.  Or connect to the black copper wire that is my load "loop"?  I am also confused on your comment about neutral passing to load.

Thanks for your expertise!

ScottMan wrote

1. line

2. master - connections out on travelers 1 and 2, as well as neutral

3. satellite 1 - travelers 1 and 2 connected to switch and output, neutral pass through

4. satellite 2 - takes travelers 1 and 2 with load connected to traveler 2, neutral passes to load

5. load

Note this is essentially replacing the 4-way with a satellite where the input/output travelers are connected together.

  @Indecision, my configuration was line coming into box #1 and load in box #3. Yours is line and load in box #1. This works, but you just have to bring the line back on the third wire like you are doing. So in the third box, you connect both traveler #2 and your load (black) wire to the traveler #2 screw. You won't have neutral in box #2 or #3, but you don't need it.

Hope this is clear!

@ScottMan, thank you so much for the reply.  I tried it this evening and can't get it to work.  I am using the V2 switches and they definitely wire differently than V1.  I ordered the V1 version of the switches from Amazon and will give it another try later this week.

I have tried every combination of wiring I could come up with for the V2 switches and it is going to take someone smarter than me to figure it out.

Thank you again for the help!  I will report back after installing the V1 versions.

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

  @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?