Postfix relay to using TLS1.2

in flag

I use Postfix v3.1.15 to relay emails from my own internal systems (alerting, backup reports etc) to to be delivered to my O365 mailbox.

I've been using Postfix installed on Debian 9 for this for a couple of years. However I am receiving emails from Microsoft informing me of depreciation of TLS1.0 and TLS1.1 soon and to use TLS1.2 going forward as they have detected I am still using TLS1.0/TLS1.1.

Is there a simple command I can initially ascertain which version of TLS I am using currently? I am no Linux expert and each time I need to revisit anything Linux based I have to teach myself all over again as I do not administer Linux on a daily basis.

TY in advance...

My is as follows:

# See /usr/share/postfix/ for a commented, more complete version

# Debian specific:  Specifying a file name will cause the first
# line of that file to be used as the name.  The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname

smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no

# See -- default to 2 on
# fresh installs.
compatibility_level = 2

# TLS parameters
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname =
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = $myhostname,,,
relayhost =
# mynetworks = [::ffff:]/104 [::1]/128
mynetworks =
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all
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