Zabbix graphs are awesome for watching performance trending of servers over time, but what is missing from those graphs is to add date markers of important releases on your servers, so it is easier to see performance changes which are a consequence of a particular release/change on the server.

This could be implemented by adding a separate tab called "Date Markers" (or whatever) and on that tab you will be able to add a new date marker by giving it a:

• name
• selecting a date
• selecting the hosts to which this date applies

The graphs should also have a check-box somewhere in the interface to enable/disable the display of those markers.