Upgrade Ubuntu Ubuntu 16.04.1 LTS to Ubuntu 16.04.3 LTS

First of all you have to check Ubuntu end of life:
https://www.ubuntu.com/info/release-end-of-life

2. You can used this step to upgrade your ubuntu;
Ref: https://www.digitalocean.com/community/tutorials/how-to-upgrade-to-ubuntu-16-04-lts

3. But when you run apt-get upgrade
    You got error run apt-get -f install .
This maybe because of your /boot is already fully utilize 100%.

Here is the step to solve it : Ref: https://askubuntu.com/questions/345588/what-is-the-safest-way-to-clean-up-boot-partition

Or you can used Ref: http://www.mogilowski.net/lang/en-us/2014/04/14/remove-old-kernel-packages-from-ubuntu/

4. If you have problem while upgrading nginx:
EG: Errors were encountered while processing: nginx-extras

•   You have to check what web service that you use? 
• If you are using Apache, remove pkg  : apt-get remove nginx* 
• If you are using nginx, stop the apache service.
• Ref: https://askubuntu.com/posts/805283/edit

5. Check your version 

lsb_release -a

Upgrade freebsd 10.3 to 11

Ref:
1. https://sysadmin-note.ru/obnovlenie-freebsd-s-10-3-do-11-0/
2. https://www.linuxsecrets.com/en/entry/51-freebsd/2017/08/30/2926-upgrading-freebsd-11-0-to-11-1

housekeeping old files

find /path/to/check/ -name '*.sql' -type f -mtime +6 -exec rm -rfv "{}" \;

delete file older that +n day

https://www.cyberciti.biz/faq/how-do-i-add-jobs-to-cron-under-linux-or-unix-oses/