I forgot to report another problem, but i can't say if it was also in the old firmware or in 4.7.0 op21, my provider uses ipv6, and uses map-e to get the ipv4 address.
The problem is that the slow opening of the pages that i had reported before i discovered that it depends on ipv6, if i disable it from the clients the problem disappears and navigation is fast and fluid.
This problem did not exist with the previous router, a fritzbox.
Unfortunately i cannot disable ipv6 from the router otherwise the line no longer works.