Generally the system will make you aware of any changes to events you are attending - such as if the start or finish times have changed. You can customise what you are notified about via one of the following settings;
- No notification - I would rather not be updated about any changes to times, rosters, and event details
- Any roster additions and withdrawals - only notify me when I'm added or removed from a roster
- All roster changes - notify me of any additions, removals and changes your rosters or event details
Note, some event notification settings can override this.