ICMPv6: process `sysctl' is using deprecated sysctl (syscall)

[16677.793938] ICMPv6: process `sysctl' is using deprecated sysctl (syscall) net.ipv6.neigh.br-lan.base_reachable_time - use net.ipv6.neigh.br-lan.base_reachable_time_ms instead
[16677.897121] nr_pdflush_threads exported in /proc is scheduled for removal

Is this a question? These warnings are normal and harmless.

Thanks @jow
How turn off these warnings, or is there a more sensible way to change them?

I think there is no way to disable these warnings apart from not using sysctl.