Setting up a test server with v1.11 on 20.04 LTS, (apart from the warnings saying if I break it I own both halves) the only thing out of the ordinary so far is the result of the unattended script install of SMTP (SES) which gave me the following...
postmap: warning: /etc/postfix/main.cf, line 46: overriding earlier entry: smtp_tls_security_level=may
postmap: warning: /etc/postfix/main.cf, line 32: overriding earlier entry: smtp_tls_security_level=encrypt
postmap: warning: /etc/postfix/main.cf, line 46: overriding earlier entry: smtp_tls_security_level=may
postmap: warning: /etc/postfix/main.cf, line 32: overriding earlier entry: smtp_tls_security_level=encrypt
postmap: warning: /etc/postfix/main.cf, line 46: overriding earlier entry: smtp_tls_security_level=may
postmap: warning: /etc/postfix/main.cf, line 32: overriding earlier entry: smtp_tls_security_level=encrypt
postmap: warning: /etc/postfix/main.cf, line 46: overriding earlier entry: smtp_tls_security_level=may
postmap: warning: /etc/postfix/main.cf, line 32: overriding earlier entry: smtp_tls_security_level=encrypt
postmap: warning: /etc/postfix/main.cf, line 46: overriding earlier entry: smtp_tls_security_level=may
postmap: warning: /etc/postfix/main.cf, line 32: overriding earlier entry: smtp_tls_security_level=encrypt
postmap: warning: /etc/postfix/main.cf, line 46: overriding earlier entry: smtp_tls_security_level=may
postmap: warning: /etc/postfix/main.cf, line 32: overriding earlier entry: smtp_tls_security_level=encrypt
postmap: warning: /etc/postfix/main.cf, line 46: overriding earlier entry: smtp_tls_security_level=may
postmap: warning: /etc/postfix/main.cf, line 32: overriding earlier entry: smtp_tls_security_level=encrypt
postmap: warning: /etc/postfix/main.cf, line 46: overriding earlier entry: smtp_tls_security_level=may
postmap: warning: /etc/postfix/main.cf, line 32: overriding earlier entry: smtp_tls_security_level=encrypt
postmap: warning: /etc/postfix/main.cf, line 46: overriding earlier entry: smtp_tls_security_level=may
SMTP was successfully enabled!