@jcp77 

I'm going to use the chart below to answer your questions.

This is part of the deco firmware platform chart. The first number in the left column is the firmware platform number. The next number in the middle column is the firmware version.

When it comes to mixing deco's of the same model but different hardware version you want to go with the one with the oldest hardware version as it's firmware will have the most options.

You have three decos on 1.6 hardware which in turn are running firmware version 1.4.1 and if we use the chart above and we look for 1.4.x we can see your three hardware version 1.6  units are on firmware platform 1.10.0 and have access to the following options 

Now the other two decos are on a newer hardware version so there on firmware version 1.3.1 so we use the chart again and we see those two decos are only on hardware platform 1.9.0 so they do not have access to the same options as the three 1.6 units

So to gain all the options of hardware version 1.6 one of those units needs to be the main unit. This link goes over how to swap a deco to a main unit

https://www.tp-link.com/us/support/faq/2400/

As for the wireguard question. Wireguard support wont be added to any of your decos till they are upgraded from firmware platform 1.10.0 to firmware platform 1.11.0 as shown in the chart below. I wish I could give you an ETA on when that will happen but I am unable to do so I will say when it happens it will probably happen to the three 1.6 hardware version units first.

  @jcp77 

So in that link you will see this 

Applies to:

Deco XE75(US/EU/AU/CA)_V2/V3
Deco XE5300(US)V2/V3

Deco WE10800(US)V2/V3
Deco XE75 Pro(US/EU/AU/CA)_V2/V3
Deco XE70 Pro(US)_V3

Vx.0=Vx.6(eg:V2.0=V2.6)

I beleive V3=V3.6 based off that chart so you "might" be able to install that beta on your 3.6 units but don't do so yet till i can cofirm it. If you can use it then you would want to install it on the 3.6 units and use one of them as your main 

I will also ask about the chart because the beta shows that you would gain access to WireGuard support with that patch which isn't a option thats supposed to be on hardware platform 1.10.0 

@Ryan 

Can you confirm if they can use this firmware on their 3.6 hardware version and did you guys change on the hardware platform chart is working? 

@Ryan   @Carl 

Please advise on this, That damn chart always throws me off lol 

Thanks 

  @HelpFixDecoApp,

The chart in the KB is quite dated at this point, truthfully - we have kept it there as models were catching up and the compatability in mixed networks is still accurate.

Essentially, after the top row (1.12.0 and 1.6.0) things became fuzzy, with some firmware versions recycling their versioning and sharing versions (despite having very different features). 

This was then further complicated by devices releasing with a mix-and-match of features on their initial firmware.

While the chart can still be used as a general rule of thumb, we really recommend checking the actual device download page for accurate info about a specific model. Now that things have leveled off, our team can start to go through and compare updates to rebuild the chart to the best of our ability.

ALSO, keep in mind that the full "equivalent hardware versions" is as follows:
 

Vx.0=Vx.6/Vx.8 (eg:V1.0=V1.6/V1.8)
Vx.x0=Vx.x6/Vx.x8 (eg:V1.20=V1.26/V1.28)
Vx.30=Vx.32 (eg:V3.30=V3.32)

I have also been planning on adding this note to the KB:

Note: This article has aged and is not updated as frequently as it once was. As Deco firmware development has progressed, feature availability and behavior can now vary by model and firmware version, making a single continuously updated list less reliable over time.

For the most accurate and up‑to‑date information, we recommend checking your specific device’s Download page and reviewing our community’s Monthly Featured Firmware Updates knowledge base article, where significant releases and changes are highlighted/summarized.

There was also a point in time where I had an Excel sheet based on our updates that could state this compatibility for even models that have had their older patch notes removed. I will see if I can rebuild it and perhaps pass it off.

  @Riley_S 

Does V3=V3.6?

If so then they should be able to use the new firmware,