Just read the announcements of new RouterOS version here at the forum, and you see why an auto upgrade is dangerous.
Nearly every new version breaks some for some user/routers, but not for all. One day it may be some config you are using that breaks.
Here is one way to do an auto upgrade.
- Make a script (that runs at boot or once a day/week) that test an external website for true/fals. As long as website says false, stop stript.
- Test the new version on a 100% equal router that you have with same config for some time to see if all works as expected.
- Read forum over and over for minimum some weeks.
- Then if all looks fine, set website to true, so that upgrade will take place.
\
Use Splunk> to log/monitor your MikroTik Router(s). See link below. 
MikroTik->Splunk
\
Use Splunk> to log/monitor your MikroTik Router(s). See link below.