Cant disable START_TLS for mails

Hi,
I have upgraded to 2.9.0.beta7.
The following setting that worked in earlier version is no longer effective.

DISCOURSE_SMTP_ENABLE_START_TLS: false

I see this topic here: FIX: Make disabling TLS in mail possible again #17024

Is the fix still required in 2.9.0.beta7? Can someone please explain how to implement the fix?

Thanks
Nagaraj