hey, what's your iOS version of iphone X? How many deco units do you have in the Mesh network? It seems it's a compatibility issue and it's better to email tp-link support directly with more detailed...

So far so good with my deco units. What kind of issue do you get with deco units? You may describe your problem here or send email to tp-link support for further help.

Hi Susan, here is a good FAQ for you. https://www.tp-link.com/en/faq-691.html

Hey, here is a good FAQ for you. https://www.tp-link.com/en/faq-2233.html

Generally speaking, we can't update to other verion. Tp-link may have their plan to update the region firmware. They can't update all the firmware at the same time. They may prefer to update those...

It seems your current firmware is special version. In that case, you can't upgrade to other common version.