via https://www.facebook.com/Tree-House-1292432357546945/

1. security patches

# freebsd-update fetch
# freebsd-update install

2. upgrade to 13.1-RELEASE

# freebsd-update -r 13.1-RELEASE upgrade
# freebsd-update install

3. reboot and apply final patches

# freebsd-update install

4. upgrade jails (using ezjail)

• find the current jail version:

# file /servers/basejail/bin/sh

• install patches for this version:

# ezjail-admin update -U -s 13.0-RELEASE

via @afpfr

• https://docs.freebsd.org/en/books/handbook/jails/#jails-ezjail