@AlanKii Sounds like you need to request a replacement, see here for instructions: https://www.tp-link.com/us/support/faq/2599/

@David-TP It has been my understanding that numbers after the "." are read in order, so: V1.6 (one point six) is actually an older model than V1.26 (one point twenty-six). At first glance one may...

@David-TP "Vx.0=Vx.6, such as V1.0/V1.6, V1.20/V1.26, x.6/x.8 is used to identify the place of production." This is very confusing. Is it possible to please re-explain this? I notice as time moves...

@BIGJJ Any AX3000 rated Deco would be a good choice such as X3000 or X55. The mesh is limited by the lowest specification Deco so keeping them all the same is a good idea.

@Nate73 Hopefully helpful... https://www.tp-link.com/us/configuration-guides/quick_setup_guide_for_standalone_omada_eaps/

@Madmonkey150 Consider switching x20 <-> x55 and use one of the x55 as router, then retest...