Sub 1 sat/vbyte setting?

How do we enable start9 node with bitcoin core to accept and relay sub 1 sat/vbyte?

Hi there!

You change this value in Bitcoin config > mempool > Min Transaction Relay Fee.

Hi, it seems like this setting doesn’t exist for me?
Core 29.2.0~1

Under mempool i see:
persist mempool
max mempool size
mempool expiry
enable full rbf
permit bare msig
relay op return
max op return size

What’s weird is I do recall being able to tinker with this setting not long ago in start9, so something must have changed recently.