Have a look at

See also in the documentation:

If you are connecting to a mail server with a self-signed certificate and want to skip the SSL verification, you can also pass an additional argument novalidatecert with the value true.

https://docs.laminas.dev/laminas-mail/read/#using-remote-storage-protocols

Have a look at

laminas-mail/src/Protocol/ProtocolTrait.php

Line 40 in 1ee1a38

public function setNoValidateCert(bool $novalidatecert)

Yes this is of course true but there is missing:

'allow_self_signed' => true,

This line here:

private function prepareSocketOptions(): array { return $this->novalidatecert ? [ 'ssl' => [ 'verify_peer_name' => false, 'verify_peer' => false, ], ] : []; }

Ah, it's a feature request.