Am I right to assume certificate renewal with the same filename requires a dovecot reload/restart

[Guido Goluke, MajorLabel]

Running dovecot 2.2, apologies if this question has been asked before: 
I've done the research but couldn't find anything.

I run a server that uses dovecot as a MUA for Postfix and have a Let's 
Encrypt certificate that auto-renews through certbot on Ubuntu server 
16.04. Dovecot did not pick up on the new certificate for the hostname. 
It did after a restart. To be clear: Let's Encrypt overwrites the 
previous certificate using the same path and filename. Am I right to 
assume that Dovecot needs a reload/restart after the certificate has 
been renewed in order to 'pick up' on the new certificate and if so, 
would I require a reload or a restart?

Thank you in advance

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MajorLabel