[mail-crypt-plugin] How to decrypt mailbox?

How do I enable the mail-crypt-plugin globally? Do I have to place 'mail_plugins = $mail_plugins mail_crypt' inside ever conf.d file where there is a protocol code block? Like for example the protocol lda codeblock in 15-lda.conf and the protocol imap codeblock in 20-imap.conf

I placed 'mail_plugins = $mail_plugins mail_crypt' in 20-lmtp.conf inside the protocol lmtp code block, and the actual plugin settings are inside 90-plugin.conf inside the plugin codeblock. And I was able to get CRYPTED mail with this config.

If I place 'mail_plugins = $mail_plugins mail_crypt' inside 90-plugin.conf, I get an error telling me to put 'mail_plugins = $mail_plugins mail_crypt' in 20-lmtp.conf

Sent with ProtonMail Secure Email.