hi
what speeds can Mikrotik hEX s support with SFP GPON?
on the mikrotik app i can see that the SFP port could support up to 10G but i am not sure that the box itself could support it
on spec page it says 1.25Gbit/s SFP cage

so for the next level to support 2.5G i have to upgrade to https://mikrotik.com/product/rb5009ug_s_in right?

No Mikrotiks support dumb GPON SFPs, it is possible to use smart GPON SFPs which contain a processor handling the GPON to 1000BaseX protocol conversion - however the SFP interfaces on some Mikrotiks are fussy as to what they will support. See viewtopic.php?p=742273#p742273 for more detail.

Since then some Mikrotiks with 2.5Gb ethernet interfaces have been released, there is nothing to indicate that the SFP+ interfaces will operate at 2.5Gb.